Holy Trainer v3 Nub review

I’m placing this review behind a jump since it’s filled with NSFW images of a teeny-tiny chastity device doing its job…

There’s a concept in evolutionary biology known as Cope’s Rule that says organisms tend to increase in size over time. I was thinking of that — or rather, the inverse of it — as I was pondering how to review the Holy Trainer v3 Nub. You see, in the…oh, god…more than ten years I’ve been wearing male chastity devices, they have been evolving into decidedly smaller things. Downright tiny, even. And now, here we are at what is perhaps the most extreme version of such small devices. At least, the most extreme I’m aware of. The most extreme I can conceive of. A device so wee that terms like “tube” and “cage” don’t seem to make sense. It’s more of a cup. A tiny, little penis head-sized peanut. But, it’s where we are and, in ways I never would have predicted ten years ago, it totally works.

I’ve felt for a while that smaller devices are better for most men. And I think the fact that most popular mass-produced devices now come in smaller sizes shows that a lot of people feel that way, too. In my experience, the closer a chastity device tube is to the actual size of one’s erection, the less comfortable it is. But what about nearly non-existent tubes? Tubes that aren’t much bigger than the head of a penis? Um…yeah. Actually. Even them.

Snug as a bug

In 2017, I reviewed a similarly tiny device I dubbed Micro (it’s a super cheap, anonymously produced steel Chinese piece that doesn’t have a name as such). That device is very simple: A base ring with a small cap held on by an integrated brass cylinder lock. While not uncomfortable, the Micro has at least two downsides. First, it’s impossible to pee standing up while wearing it. The cap has one hole smack in the middle and a bunch of smaller holes surrounding that, while urinating, approximates a sprinkler head. Second, the central hole is just big enough to push a little nubbin of penis flesh through and, since there are so many nerve endings in that part of the body, a little nubbin is more than enough to cause a lot of sensation (usually not good) when rubbing against underwear or the inside of pants, etc. A third more subjective issue with the Micro is that while the penis is attempting erection, it ends up with a bit of shaft showing behind the base ring. As someone who prefers to see and feel zero exposed penis, that’s a negative.

The Nub fixes all these issues. The opening of the tube lines up perfectly with the opening of the urethra and presents it forward rather than down. I wore it for this review over several weeks and peeing just worked. And not like with the Steelheart where the urine trickles out the end thanks to gravity. Peeing through the Nub is the only time I’ve ever been in chastity and had what felt and even sounded like a natural experience. I literally did nothing at all and it worked as expected 98% time. Just like a real boy.

It just works.

Not only is the opening seemingly always in the right place, there’s a slightly raised lip around it that protects the tip of the penis from making contact with surfaces like underwear or the inside of pants. I have barely felt any contact with the tip. Even when going commando, which is something I could never do in the Micro, I was pleasantly surprised by the lack of sensation. Same goes in bed from sheets. Not even while laying on my stomach. It’s a tiny and thoughtful design feature that makes me think this is a device made by those who actually wear chastity devices and who care about other men who do.

Contents at rest
Contents engaged

The other area where the Nub is better than the Micro is in concealing its contents, in both their squishy, flaccid state and when straining. The secret to its success is, I think, due to the unique tube flange that all Holy Trainer sizes have that protrude behind the base ring. I’ve seen some guys say they can’t wear HT devices due to this flange, though it’s never bothered me. Until the Nub, I haven’t understood why it was there so I can’t tell if the way it works on the Nub is the way it was intended to or if it’s a happy accident. In any event, unlike with the Micro where the penis is essentially squished down like a springy snake into a novelty can of nuts, the flange on the back of the Nub catches the loose skin on the shaft. I’ve made an animated GIF to demonstrate this. Pardon the dry skin. Winter is long north of the wall.

Hot flange action

As I said, the Nub tube is the only Holy Trainer size in which this flange interacts with my body like this so I can’t know if it’s an intentional aspect of the design but the result is an incredibly snug and secure-feeling fit that makes the Nub feel more integrated into me than any other device I’ve worn.

So much so, that it basically turns the penis into an internal organ. The entire shaft, whether flaccid or hard, remains inside my body and after a while I felt like I didn’t even have a penis. In one of the images above, you can see how when hard the erection manifests as a sort of lumpy bulge behind the Nub. During very intense erections, the shape of it can be seen in the bulge, but the entirety of it remains inside.

Belle and a lot of people on Twitter assume the Nub is painful and uncomfortable, especially when it’s containing an erection, but nothing could be further from the truth. It’s incredibly comfortable, even when the penis is trying to be erect. Unlike most other trapped-ball devices I’ve worn (maybe all trapped-ball devices I’ve worn), the Nub doesn’t pull against my balls when containing an erection. There’s no testicle pain from the tightness of the ring because the thickest part of the erection doesn’t go through the ring. Just the head.

Low profile

From a stealth perspective, the Nub excels. Unlike the Micro which created an almost inverted bulge when seen through clothing, the Nub’s presentation looks very natural, though the bulge it makes is nearly entirely made up of my balls.

Nothing to see here. Move along.

Hygiene can be tricky in this device. It’s so sung and integrated with its contents that it can be difficult getting soapy water behind it. I will just as often than not withdraw the penis from behind to make it clean and then reinsert it. Yeah, that’s not ideal, but it’s the most efficient. I’m sure one could keep it clean enough without doing that, though. Since I have a PA and the piercing goes empty while I’m in the Nub, I do get extra leakage of urine that gets trapped behind the plastic. My assumption is men without extra holes in their penises would find the Nub to be very hygienic.

And yeah, as snug as it feels, it’s no more secure than any other trapped-ball device that’s not fixed with a PA or some other piercing. Alas. But it feels very secure and that’s half the battle.

In summary, I think the Nub is a terrific male chastity device. It’s effective and creates almost no discomfort. While I greatly prefer steel and devices with the absolute security of a PA fixing, the Nub is a device I could (and have) worn for weeks at a time. It’s become my go-to travel device. For those seeking a device that maximally minimizes its contents, the Nub should definitely be considered.

47 thoughts on “Holy Trainer v3 Nub review

    1. That’s a good question that, being cut myself, I can’t answer fully. I would think it’d be OK, but it would probably make getting everything squished in there harder.

      1. Maybe the plastic at the back of the cage, helps push all the skin back. Is it best for uncut foreskin to be pushed back when in these small cages, anyhow?

  1. Thanks, good and informative review, I have just ordered a nub device from China after reading a review

  2. Thank you for such a good review. I’m considering purchasing one myself but was concerned about “fitting” inside. I’m an average sized male and just don’t want to spend the money and not be able to use the nub.

  3. I’ve been wearing it instead of the metal Micro device. It IS very comfortable indeed, peeing is not a serios issue.
    I love it.
    But there is a disadvantage: it is not (yet) available as a stainless steel version and it is not (yet) available as a urethra-friendly plug or adapted version. I love this kind of equipment very much which can prevent, if long enough, a pullback of the penis. I use a corkscrew-plug instead, but that makes it necessary to remove the cage for cleaning.
    You want to try? Check Ali or DH and then get the original pretty pricey one.

    1. I just learned(info from the distributor) that there is not going to be an original Nub as stainless steel version. So it is going to be hay day for clonemakers…

      1. Steel v4 clones are out there now, no idea how nasty the material is.
        They seem to miss off the anti-rubbing lip, in pictures i’ve seen…

  4. What is the color of the Nub that you are wearing: black or translucent black?
    Apparently black is standard, but translucent black is an extra-cost option. I’d like to be able to see a bit of what’s going on “under the hood,” but dark enough so that it is unmistakable that I’m locked in a chastity device. That leaves me with something between clear and solid black: hence my interest in translucent black.

      1. How about asking HT for a HTv4 nub to try / or making specific suggestions towards HTv5 ?
        I wonder if there should be a variant between the nano and nub and versions to reduce the overall bulge under lycra workout kit.

    1. I bought a Chinese version and it was delivered today (just over a week from ordering so not bad) , tried it on earlier for an hour and have to say is was incredibly comfortable to wear.

  5. Thanks for the detailed review, which a review by Caged Lion confirms. He found a Chinese version for about $35. You say it’s become your go-to travel cage–you haven’t had any trouble getting through airport security wearing it? Have you done it multiple times?

  6. Thanks to this review I purchased mine from DHGate which arrived yesterday (10 days after I ordered) and today I am wearing it for the first time. Coming from the CB6000s whose base ring is way easier to assemble, The Nub presented a challenge at the beginning but once the base ring fitted behind my balls the cage came in place easily. It is surprising to see the penis almost disappear above your ball sack. One thing to say, so far is way more comfortable than the CB6000s.

  7. When I get an erection in this specific device, my penis has not resisted the device and then receded inside my body but rather it pushes the whole device forward. I have gotten the next ring size smaller, tested with the erection, and it still pushes the whole device forward and it looks nothing like what you have shown about it going back inside you. I was using lube at the time and I was really surprised because I was even able to “pop” out of my device with a strong enough erection (without using my hands). I think I am going to stop using lube to prevent the device from pushing forward so much and from it popping out. I still do not know how you keep the ring so close to your body. Fantastic review by the way. I was really intimidated by the size of the nub but you are right, it is super comfortable. It feels more secure but I am unsure if it is actually more secure. Either way, it is a step up from the “small” size IMO.

      1. this is my same question. I use the standard size and i have this same problem. my penis pushes the Ring and cage out from my body. how do i keep the ring against my body all of the time?

      2. My Nub fits just like the photos. My balls tend to be high and closer to my body so they keep the ring tight against me. (I even have the extra skin held back by the flange as in the .gif) I would think that if one’s balls hang lower the entire ring would slide down and would be not close to the body.

    1. I dunno! All penises are special little snowflakes. Could have something to do with differences in erect sizes between us? Or perhaps the amount of slack in our ball sacks? I mean, I didn’t do anything special except put it on and was amazed at how it fit.
      The other micro device I’ve worn did what you guys are saying. But not the nub. I guess I don’t have a tidy answer.
      Curious to know how but your erections are. Both length and girth. Do you know? Maybe you’re just bigger than me?

      1. I am not circumcised (the extra skin could push it forward a little)
        Flaccid Length: 3 inches/ 7.5 cm
        Flaccid Girth roughly: 4.25 inches 4 1/4 inches/ 10.7 cm
        Erect Length: 5.5 inches, 5 1/2 inches/ 14.5 cm
        Erect Girth: 4.88 inches, 4 7/8 inches/ 12.4 cm
        Ring Size: 45mm – 40mm

  8. Wearing my new nub which I got yesterday. You were right about everything. This thing is very comfortable.

  9. Excellent posting. I have been wearing the HT v3 nub size for several months, and it is comfortable, hygenic, and secure. I have an exceptionally small penis, and my v2 small and then nano penis holders were too large for me, and the entire device used to slip off when my penis retracted into my body, which it does during most exercise. The v3 nub fits perfectly, and it has never come close to slipping off. If HT came out with a design that might be called “innie” where there isn’t even the .9″ protrusion of the nub size, I’d definitely try it.

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  11. Remenber all that the Chinese version if the NUB is not similar to the real HOLLY TRAINER NUB.
    the Lion from male chastity device say it clearly also.
    The angle are differents wich explain why some don’t really fit well.
    I modified my chinese nub but will invest in a real one soon.
    I hope also HOLLY TRAINER will do a CASTRA ONE , with smaller diameter and half lengh for micro penis.

  12. I have been wearing a knock-off version of the Nub for about a month now and have to say it is the most comfortable device i have ever worn having invested hundreds of dollars in a silicone cage from lockedbird and a clear resin Vice. To those who see it and think it looks painful, they should know that it is not. It even surprised me how comfortable it is after a few days i forget i even have it on. Love it under my clothes and also at night when sleeping. You can stand to pee (especially at a urinal) as the stream is perfect albeit a little stronger than usual. And I have a PA hole on the underside of my shaft which seems to close up because of the small space in the Nub, so all of the urine comes out the pee hole which is great. Like the review says the larger devices allow you to get hard inside which i found causes pinching and pain in my balls during night time erections. I don’t know if the Nub is preventing me from getting hard at night, or if the erections are being pushed inside me, but I do not have any night time pain which wakes me up. Have to say that for me smaller is better when it comes to a male chastity cage.

  13. The Nub was my fourth cage. The first two were steel Chinese models with a hinged base ring. They were excruciating after a few hours even after trying tricks like lube and a bit of nylon etc. My third cage was plastic and pretty much a cb6000 knock-off. I bought it to try plastic for a change and plus it had 4 ring sizes to experiment with. The base ring was painful on it as well , but not as bad as the first. Then came the Nub… No contest, it was by far the most comfortable. I am uncut , and there was a bit of an issue tucking the ‘under-foreskin”. and I had to lightly sand the device in that area. A cut penis probably wouldn’t have came into contact with that part. I still had a bit of sac chaffing, particularly while driving. Even so, I went two weeks in the device where before I was lucky to go 14 hours. Having said that… don’t go 14 days … We were over zealous about it fitting so nice and went to far for hygiene purposes lol. I’d say it’s good for maybe a week tops depending on climate and living styles etc. I am now on my 5th device. I went back to metal with a rounded base ring rather than the flat band like rings. TAKE NOTE her fellas… flat band like ring = BAD BAD BAD. My keyholder wants me to go a month without an unlock is the only reason I’m not using the Nub. That hygiene thing again. Having said all that , the Nub is still my favorite, just wish I was circumcised.
    Maybe someone will figure out a way to make a cage type of one. If they do.. it would be my last cage ever.

  14. Can anyone tell me the psychological effect of eliminating their penis this way? More submissive? Girl thoughts? The effect it has on dominance?

  15. I just unboxed my V4 Nub a few hours ago and could not wait to lock myself. My keyholder allowed me to unlock my V4 Small (she uses a Bluetooth controlled lock to control my access to the key). Within two minutes, I put on the new ring (using 40 instead of 45mm now) and got into the nub. It’s insanely comfy, and my manhood is entirely gone. I sent a photo to my owner. She loves the look, and she said she will be licking my locked-up clit when we meet next time.

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