Karl’s Introduction to Pumping - Part 3 - Adjuvants (Massage, Bundles, Heat, Vibration), debunking water pumping nonsense, length pumping explained.
This blog post was from Karl Wikman's PE blog. He is a moderator on the subreddit TSoPE
His blog can be found here.
And his reddit can be found here.
tl;dr:
In Part 3, we delve into pumping adjuvants — enhancements like bundled stretches, 850nm infrared heat, and vibration, plus techniques such as water-, sleeved-, and length pumping. We debunk myths (e.g. water’s supposed superiority) and detail how each method can boost tissue expansion, reduce edema, or trigger cellular growth via mechanotransduction or photobiomodulation. Ultimately, these adjuvants serve as advanced troubleshooting tools when simply increasing pressure isn’t enough, encouraging you to tailor your routine with scientific rigour and personal experimentation.
Introduction
Welcome to part 3 in my guide to pumping. I have previously explained static-, interval-, and rapid interval pumping, recommended equipment and routines for each, debunked a myth about the importance of being erect while pumping, written about key pumping safety considerations, and how milking is pure magic for your erection quality.
In this third installment of my guide I will take a look at the role of tunica work, heat, vibration, water pumping, length pumping, and sleeved pumping. I will be debunking some myths along the way. Let’s jump right in:
Pumping Adjuvants
An “Adjuvant” is something (such as a drug or method) that enhances the effectiveness of a medical treatment.The prefix “ad-” is self-explanatory, “-juvant” comes from the latin verb “juvāre” which means “to help/assist”.
Bundled Stretches
I have already mentioned warm-up exercises such as taking a hot shower and doing some massage, V-Jelqs, tunica presses, etc. In that context I mentioned bundled stretches of different kinds — and those are really effective when it comes to triggering MMP release and inducing tunica softening. The effect actually peaks at around 6 hours or so after the stretching stimulus, if the medical literature I have looked at is to be believed.
If you are doing a mixed protocol that involves both lengthwork and girthwork, I 100% recommend doing bundled work prior to girth sessions. As little as ten minutes of bundled stretching will tend to help increase session yield in subsequent pumping. I don’t do much lengthwork myself, and I don’t consider bundles warm-ups an absolute necessity, so this is not something I think you should add if you are not already doing lengthwork. But if you do, make sure to include some bundled work, and to do the lengthwork before the girthwork to reap the benefit. However; I have seen occasional comments from people who found bundled work actually decreased their session yield in subsequent pumping — so as with all PE you need to experiment with it and see if it does something for you.
Heat
I frequently see people mention they use a rice sock or hot towel to heat up their penises before PE. It’s not completely wasted time, since it might help your nervous system relax a little, but in terms of inducing tunica malleability it’s going to be a negligible effect. The penis has an effective cooling system in the form of blood circulation, and it quickly loses the temperature you add to it. Within a minute or two, you are back to baseline.The way around that is to simply use an infrared heat pad around the cylinder while you pump. It needs to be one that radiates photons in the 850 nm wavelength or thereabouts. That is a region where acrylic is quite translucent and your skin too, meaning the energy can reach all the way into your penis and heat your tunica without heating your skin too much causing discomfort. Direct contact heat pads that work at much longer wavelengths will tend to heat only the cylinder, making it quite painful when your penis touches it long before your tunica will reach meaningful temperatures that could aid malleability. Those are nice for lengthwork where you can apply them directly to your skin.
In a comment I wrote somewhere, I expressed it rather succinctly: “IR heat when pumping has the benefit of being transmitted to the tunica with minimal losses in the acrylic, and without heating the pump to where it scorches your skin. The heat makes your tunica more malleable, making it easier to break hydrogen bonds between fibrils (crosslinks), and thereby makes for less damage, shortening the healing time required. It can also increase MMP release and stimulate fibroblasts to release other growth factors, and generally improves chemical reaction times in the tissue. If used sparingly it is anti-inflammatory. If overdone it is pro-inflammatory. Heat can also make your glans dry and prone to blistering, so ideally you should use plenty of lube and screen off the IR from the glans with a piece of aluminium foil for instance.” I will add just a tad more detail to that surface level comment:
The benefits go beyond just making the tunica more pliable — there are also so-called photobiomodulation (PBM) effects due to the fact that many cell types have receptors for infrared light. 850nm NIR light has been shown to directly stimulate fibroblast proliferation and extracellular matrix (ECM) remodeling — great for tissue growth and recovery (Mussttaf et al., 2023). PBM at 850nm modulates inflammatory responses by reducing TNF-α, a key inflammatory cytokine, while promoting IL-1β, which is involved in tissue repair (ibid). This means that in addition to making your tunica more workable in the moment, the IR exposure also supports tissue adaptation at the cellular level; it reduces inflammation and promotes collagen synthesis and angiogenesis — meaningful for long-term gains and recovery (Cuerda-Galindo et al., 2015).
VEGF (vascular endothelial growth factor) expression is another factor influenced by 850nm PBM, increasing blood vessel formation in the targeted area. More endothelial tissue stimulus in the cavernosal sinusoids means better “filling in the sausage” and also improvements in erectile response, which should allow tissues to oxygenate and repair faster (Khoo et al., 2014). FGF (fibroblast growth factor) production also ramps up, which helps maintain tissue elasticity and reduces scar-like fibrosis, which is the enemy of flexibility in PE (Danno et al., 2001).
How much 850nm NIR will pass through the tunica? We don’t know, but the study “Depth of penetration of an 850nm wavelength low-level laser in human skin” (Esnouf et al. 2007) measured light transmission through human abdominal skin. They found that 66% of 850nm light was attenuated after passing through 0.784mm of skin. Meaning 34% made it through. I expect less than this will make it through the dense fibrous tunica albuginea, but there will certainly be some that gets through. And whatever will not make it though will be deposited as heat, which is the main effect we are looking for. In “An Experimental Study on the Penetration of 850nm and 940nm Infrared Radiation into Porcine Tissues” (Jin-Min Lee and K. Kim 2019), they investigated how deeply 850nm near-infrared light penetrates biological tissue. The study found that 850nm radiation penetrated up to 65mm into porcine tissue.
So, while a hot towel or rice sock might be comforting, if you’re serious about optimizing gains and recovery, 850nm IR is probably a meaningful addition to pumping. Just make sure you don’t overdo it! Prolonged, high-intensity exposure can flip the switch from anti-inflammatory to pro-inflammatory, which can lead to excessive collagen deposition and hinder elasticity rather than improve it. Moderation, as always, is key. 850nm NIR also increases TGF-β1 which stimulates fibroblast differentiation into myofibroblasts, which are responsible for excessive collagen deposition and fibrosis (Danno et al., 2001). This is why I suggest that people use NIR in moderation. It’s an open question where the ideal balance lies. I personally feel comfortable using NIR up to 3–4 sessions per week, for about 20 minutes each time, of which only the first 10 minutes are at strong intensity. You do you.
Hink u/Hinkle_McKringlebry discusses the pros and cons of NIR in this video — not using the same studies as the ones I used above — lending further credibility I believe, to the potential upside: https://www.youtube.com/watch?v=l8oWCIKiasg
(Open the link in a separate tab so you can watch it after reading this post)
Also note that he mentions potential benefits to erection quality. Admittedly, mice have thinner penises than humans and so more radiation will reach their endothelial tissue by orders of magnitude, but it’s still an interesting study he cites: Light Emitting Diodes (LED) as a Potential Therapy for Erectile Function: A Preclinical Study in a Cavernous Nerve Injury Model (The Journal of Sexual Medicine, Volume 21, March 2024)
Side note: Don’t buy the IR flashlight he shows in the video. It’s much easier to just wrap an IR heat pad around the cylinder. Full post explaining why here:
Post: Don’t buy $80–300 NIR + RLT “flashlights” when a $40 NIR+RLT heat pad can do the same thing in a more convenient manner, and has additional benefits.
A little note on heat application while pumping: The penis has an effective cooling system in the form of blood flow. It works pretty much exactly like a water cooling loop in your computer or combustion engine. In order to increase the effectiveness of heating, you can apply gentle blood flow restriction in the form of a couple of toe shields at the base, or a tight pump pad — when pumping we are not looking for an occlusion of inflow, just a restriction on venous outflow, so it needs to be gentle. If you do PAC (pump-assisted clamping), you have all the BFR you could ever want in the form of the Python/Fenrir clamp, and in that case you are looking for total occlusion.
We have links to suitable 850nm heat pads in the vendor list. If you don’t want to hunt around for the right kind on AliExpress or Amazon, just get the OEM product from TotalMan (featured in my review); it’s the same exact heat pad but with an added logo. Whichever heat pad you buy, make sure you can see the diodes with the naked eye.
Vibration
First off: Vibration is dangerous if done in an oversized cylinder where your dick can flop around and bang the walls. Don’t do it. I have seen several comments from people who vibrated their dicks in oversized cylinders and gave themselves abrasions and lasting pain. One guy even bled a little from his urethral meatus.
In a cylinder where your dick can’t flop around, i.e. a tight cylinder which you “pack” more or less completely, vibration is transmitted well. Vibration itself can be a stimulus for fibroblasts through mechanotransduction as previously described. It can trigger release of MMPs, increasing malleability and making crosslinks easier to break, giving you more “session yield”. It also feels rather pleasant and can allow you to endure rapid interval length-pumping protocols that would be a little unpleasant without it — the PhalBack protocol being a prime example.
Drawbacks with vibration are that it will cause friction, tends to increase edema, and increases blister risk if insufficient lube is used. Vibration over-exposure can also cause vasospasm and potentially “HAVS” (Hand-Arm Vibration Syndrome, but for the penis of course). I have written several long articles about vibration and will not repeat them here.
One special word of warning: Strong vibration used at high pressures in the cylinder will tend to cause the cylinder to bang quite hard into your pelvis. If you are using a tight cylinder (as you should be doing with vibration for the reason previously stated), this will cause a pressure-point at the top of the base of your penis right on the suspensory ligament and the insertion of the dorsal nerve bundle. In my view, it is REQUIRED that you use a properly shaped flange to spread the load over a large surface and create a gentle curve without pressure points. Companies are working on making such flanges available, some surplus is still available from a group-buy (link in our vendor list for as long as there is stock left). Another option is to use a good thick silicone pad with a gentle inner curve, such as the ones I talked about in parts 1 and 2.
If you want to dive really deep on vibration, my most important posts are these:
We need to talk about VIBRATION (part 1) — The science, the physics, the collagen, the metalloproteinase, the importance of direction and strength, resonance, numbing, and also the DANGERS if done to excess.
https://www.reddit.com/r/TheScienceOfPE/comments/1hr0mr2/we_need_to_talk_about_vibration_part_1_the/
We need to talk about vibration (part 2) — beware of banging the dorsal nerves — an even greater danger people doing DIY “Poor Man’s PhalBack” clones need to be aware of.
We need to talk about vibration (part 3) — What do vibrator ratings actually mean? RPM? “lbf”? “20kg”? My attempt at explaining the physics simply, including crucial and non-intuitive safety concerns.
We need to talk about Vibration (part 4) — Why the Derisive Remarks about “power tools” or “industrial/concrete vibrators” are Simply Based on Ignorance
If you want to dive into the world of DIY PhalBack-style “RIP with vibration” you are welcome to join the DIY discord. Hit me up on the TSoPE discord and I will give you an invitation link (trying to prevent the DIY discord from becoming a general PE discord by not sharing the link unless someone actually intends to DIY stuff).
A quick side note on direction: In the DIY PB community, we recommend aligning the rotational axis of the vibrator perpendicular to the cylinder so that the cylinder is “wanked” along the shaft of the penis. Placing it along the cylinder will make the cylinder move your dick in a circle, not wank on it. The difference in effect is modest — both orientations will trigger the mechanotransduction pathways — but only the perpendicular orientation will cause “tugs” in the lengthwise direction.
inb4: Will a small vibrator work? No, read part 3 and 4 of “we need to talk about vibration” where I explain why Newton’s laws of motion and the weight of a cylinder necessitates a large moving mass with a significant offset from its rotational axis.
inb4: Will a massage gun work? Probably yes, but only if you figure out a way of transmitting the vibrations well, and ideally to align them in the direction of the cylinder. TotalMan’s new vibration hanger might give you some ideas, since it seems to be built from a massage gun mechanism.
Water pumping
All forms of pumping previously mentioned can be done with air or water as the pressure medium. When water pumping, it’s tempting to fall for the marketing material from vendors like Bathmate with their Hydromax series, and believe that water would somehow spread the pressure better, give more uniform expansion, prevent edema better due to the back-force of the water, etc. All such claims are a load of bollocks. Let me take my favourite example of such BS:
In his “Book of Girth” (the “expansion pack”), BD writes: “Since water does not compress in a vacuum, all the pressure is applied to the penis instead of the air around the penis, making for much more even swelling.” It’s a common human failing to speak confidently about things we don’t have a clue about, and this is a prime example.
As long as air/water has a path around the object (in this case your penis), pressure changes are communicated at the speed of sound and the pressure in all parts of the medium will equalize in a manner of milliseconds in a small vessel. Admittedly, that speed is faster in water than in air, but does it matter a great deal whether it takes 0.9 milliseconds (air) or 0.2 milliseconds (water)? No, I think not.
Does water pumping feel different? It absolutely does! But the physics of creating a pressure differential over the tunica and your internal pressure pushing your penis into the cylinder in an attempt to equalize the pressure is identical. There is no significant back-pressure from the water to prevent edema, no magic ‘je ne sais quois’ about it. Don’t fall for fuzzy logic.
The main benefits of water pumping as I see them are:
- That you generally will do it in the bathtub or shower, where you can use quite hot water, imparting at least some of the malleability benefits you can get from IR use. Also, it’s an environment where your nervous system will relax and allow more vasodilation.
- That water is an incompressible medium, meaning if you limit the amount of air in your pump you can get much faster pressure variations with only a few pumps of your handle, which makes it easy to do milking even with a manual pump. This also makes Bathmate devices more dangerous than air pumps, combined with the fact that they lack pressure gauges.
The drawbacks of water pumping are that you will waste a lot of energy if you water pump 2x daily in your bathtub or take long hot showers. I’m serious about that — think of the planet! Water pumping needs to be done with a proper water trap (you can get one from a brake bleeder kit on Amazon). Those water traps are fiddly, and if you accidentally get water in your pump handle there is a good chance you ruin the pressure gauge or the whole handle.
Combining water pumping with IR heat will (1) be quite risky since you are using water and electricity in close proximity, and (2) mostly serve to keep the water warm since water absorbs 850nm NIR well. Not much of the photobiomodulatory effects of IR will be left.
inb4: But Bathmate claim that their… Well yes, of course they do. That’s called “marketing” and bears no resemblance to the truth.
Sleeved Pumping
Pumping with a silicone sleeve on your shaft sounds like a very strange thing to do. By adding a sleeve you are creating an inward pressure on your dick, which surely must counteract the pressure differential across your tunica that the vacuum creates, right? Right! That is exactly what it does — it creates a backpressure on your dick, and it does work in the opposite direction of what the vacuum does. You then increase the vacuum pressure to compensate for whatever pressure the sleeve subtracts from it. So what then have you gained? Is it not a zero-sum game?
Nope. It provides a significant benefit: The pressure the sleeve puts on your skin will keep the skin very snug against the tunica, preventing fluid from filling the areolar space between the different layers of fascia that are between the tunica and the dermis. In other words: It keeps edema at bay. The penile skin is purposely very loose-fitting and there are layers upon layers of fascia that are there to create not just structure but also give the skin an extreme amount of “gliding action”. The purpose of the foreskin is not just to protect the glans, but also to provide a “skin buffer” of tissue that can glide several inches back and forth during intercourse to reduce vaginal friction. Sadly, the space between the layers of fascia offers little in the way of resistance to fluid build-up, and the skin is loose. (That, as I discussed in previous parts, is why the claim that edema is a gains-killer is mostly just nonsense, since it will not create meaningful back-pressure against the tunica to limit its expansion).
By adding a “tighter skin” on top of your own skin, you are restricting fluid build-up. You are also resisting tunica expansion, but you just increase the vacuum pressure a bit to compensate for that, and what you are left with is a tunica expansion that feels rock hard. Remember, all of the expansion force against the tunica comes from the inside — the vacuum does not “pull” on the penis — it’s all internal forces pushing outward on the tunica. The vacuum just removes the resistance of the atmosphere.
Sleeved pumping feels very different during a session. And your penis, once out of the pump, feels different from after a normal pumping session — it’s harder and there is less edema “fluff” — it’s like the core of the penis is the only part that has been pumped.
inb4: No, a condom will not work well for this. It does not provide sufficient back-pressure.
It’s a little hard finding the right sleeve for this kind of pumping. It’s also a little difficult to get the sleeve to stay on well. I personally hate the skin-pinching that comes with putting a sleeve on my penis dry (to prevent it from sliding off).
But if you are prepared to deal with all the hassle of putting on a sleeve, and if you find the right kind of sleeve (Fkn.Mint is your friend there), and if you manage to find a way to keep the sleeve from sliding off, then sleeved pumping is sensationally good. If you combine it with PAC? Pure perfection.
With sleeved pumping, some of the vacuum will be “used up” to overcome the inward pressure of the sleeve. But here’s the kicker: You add some more vacuum to compensate, and then the sleeve will allow you to go further. Because the sleeve compresses the areolar space between the fascia, you can go rather hard with the pressure without causing edema or petechiae to skyrocket. If you wear a glans cap anchored with the sleeve, you can safely be quite aggressive with the pressure, I have found. Just make sure to take a slow and cautious approach and listen to any pain signals from your penis. Also, don’t expect this to work perfectly the first time. You need to do some experimenting to find a sleeve that works, and a method of anchoring it so it does not slide off. If only there was some silicone casting expert (ahem, u/6–12_Curveball ahem) who could come up with a method of anchoring a sleeve to a pump pad, and who could take a hint… :)
Length Pumping
A well known maker of extenders (who also has an impressive PR in deadlift) wrote a post and made a video called “Length Pumping is Stupid” about a year ago, claiming that length pumping does not work, which he had concluded from losing size over a period of length pumping at modest pressures.
Now, I like the guy. He’s a chill dude and puts out great content. But people also need to notice something: He sells extenders.
As a buddy of mine put it, that’s like a study talking about the benefits of cheese published by the British Cheese Board. Or like a manufacturer of lithium-ion batteries saying hydrogen vehicles are crap.
In a recent video, u/Hinkle_McKringlebry goes over several studies where pumping was shown to increase penile length: https://www.youtube.com/watch?v=iiPwPwTE97Q
- go watch it and read the studies he cites. So, whom do you trust? Someone who can cite studies (Hink), or a seller of a competing product who has tried it out (and his buddy who sells the same product)?
I’m in no way saying length pumping is the best thing you could possibly do for lengthwork. I hold vibra-tugging (with a vibrator “tugging” on the penis by being mounted on the crossbar) to be the king of kings in terms of rapidly giving you bpsfl “yield” from a quick session. But what I am saying is that science is on the side of length pumping here. It works.
Let’s have a look at HOW it works, borrowing from a post on my PE blog:
In a vacuum cylinder, the internal pressure in your body (which is mainly the air pressure plus the arterial blood pressure on top of that) presses the tissues of the penis into the cylinder. This results in a pressure out toward the sides of the tunica or cylinder, but also forward into the cylinder. The force “forward” is calculated as the pressure differential multiplied by the cross-sectional area. This is if you “pack” the cylinder. If you don’t pack it, it’s instead the cross-section area of your penis you need to use, not that of the cylinder. Some of the force inward will be dissipated into the walls of the cylinder due to friction, but if you use ample amounts of a good lube, you will minimise the impact of friction. The inward force on a plunger in a vacuum cylinder is called a “pneumatic force” or “pressure-induced force” if you want to consult your closest physics textbook.
By the way, the two reasons you might want to limit the sideways expansion of the penis by using a cylinder you can pack are; (1) that this allows the fibres of your tunica to be mainly pulled in the lengthwise direction, which can allow you to reach deeper compared to when you allow full girthwise expansion, and (2) that it allows the cylinder walls to transmit vibrations well to your shaft in the lengthwise direction without your glans bouncing around wildly against the walls as it would in an oversized cylinder (in case you are using vibration for this, which is not necessary but does seem to help with elongation). Conceivably you could also add a third reason; (3) that the walls being tight will disrupt the veno-occlusive mechanism, causing it to be a little more difficult to get fully erect — beneficial because a semi-erect penis will more easily be stretched than an erect one.
In a cylinder I can comfortably “pack” relatively quickly with my glans, namely one with a 1.875” diameter, at a pressure of -17 inHg (which is what I use for the final set of my routine), my penis will experience a tensile load of 102 newtons, or 23 lbs of force. Let’s say 10% is dissipated due to friction (a very high estimate I believe), and we are still at 20+ lbs. In a 2.0” cylinder which takes me a little longer to pack, the tensile force goes up to 116 newtons (26 lbs).
Here is a calculator I made for the piston force on your penis in a packed vacuum cylinder:
https://kwikmn.github.io/lengthpump-calc-by-karl/
Because I apply this force for only fifteen seconds, followed by 2–3 seconds of rest to allow the fluid beneath the skin to be reabsorbed, I have as of now never had a single blister, despite doing this routine 200+ times by now (I do it AM + PM every day — at least that is my goal).
How many people here can hang or extend at 20+ lbs of force with a vacuum cup without getting blisters? I recommend you don’t try it! If you do decide to try it anyway, I suggest you do so for only a few seconds — time of exposure is what matters when vacuum is concerned.
With vacuum cup extending, people are often limited to stay somewhere around 10 lbs of tension, or maybe up to 15 lbs if they are hardcore conditioned veterans who also know how to tape — and those guys still get blisters sometimes! That is the main reason I believe vacuum pumping for length could actually have an edge compared to vacuum extending. The reason I would still say that vibra-tugging with a vibrator on the crossbar is the king of kings is simply that the “tugs” are delivered in a direction where they perfectly align with the static tension on the extender, and that vibrations applied during length pumping aren’t causing nearly as much of a tug. Those vibrations mainly stimulate the other mechanotransduction-mediated effects of FGF and VEGF release, up-regulation of collagen deposition, etc. For tugs that significantly exceed the static force, vibra-pumping for length is a distant second to vibra-tugging. But Length Pumping is NOT Stupid. Just do it right: With rapid intervals at sufficiently high pressures for the piston force to exceed whatever force you would normally apply with an extender. Combine it with 850nm NIR heat, or with vibration if you want to, and do it after spending 5–10 minutes doing bundled stretching.
This concludes part 3 of my series about pumping.
In conclusion, this third installment has aimed to shed light on the myriad adjuvants that can enhance your pumping routine — ranging from the application of 850nm infrared heat and the judicious use of vibration, to techniques such as water pumping and sleeved pumping. The discussion has not only debunked pervasive myths, such as the supposed superiority of water over air or that length pumping does not work, but also provided a detailed exploration of how each adjuvant can, when applied correctly, potentiate tissue expansion and improve overall session yield, or in some cases reduce edema or provide meaningful stimulus on a cellular level through mechanotransduction-induced or photobiomodulatory effects on growth factor expression, cell proliferation, and modulation of the inflammatory response.
What emerges from this analysis is, I hope, a clear message: the key to maximising the benefits of pumping lies in understanding the underlying biomechanics and biochemistry, and then tailoring your approach with both scientific rigour and personal experimentation. The balance between mechanical stress, tissue recovery, and adaptive conditioning is delicate, yet it is precisely this interplay that drives meaningful, long-term gains. Pumping adjuvants should be your second step in troubleshooting pumping, when you have concluded that simply using more pressure is not a feasible way to better expansion.
As you integrate these adjuvant techniques into your routine, maintain a focus on progressive overload and monitor the response of your tissues closely. The insights presented here are intended to serve as both a guide and a catalyst for further refinement of your methods, ensuring that safety and efficacy go hand in hand. If heat gives you too much edema, try sleeved pumping and bundled stretches instead. Experimentation should be at the heart of PE, not performed by a few influencers and conveyed to people who then blindly follow their suggested protocols. There will NEVER be consensus about what constitutes the “META” (most effective tactic) of PE, and that is a good thing, because individual variations in preferences, anatomical phenotype, and mental bandwidth render a one-size-fits-all approach impossible. Use science-based insights to adapt and adjust — that is what I preach.
Thank you for following this detailed exploration of pumping adjuvants (and mythbusting). Indeed, thank you for following this whole series. I look forward to our continued journey into the science and practice of penis enlargement — where every new insight brings us one step closer to individually optimised routines and sustained progress as a PE community.
/Karl — Over and out.
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