How to measure for a male chastity device

“How do I measure for a chastity device?”

I get this question a lot. Just yesterday, someone on Twitter asked for the advice. I’ve never put it all in one place but have decided to do so for two reasons. First, it’ll make those looking for the information more likely to find it and, second, it’ll save me the time of having to say it over and over. And over again.

There are three measurements you need if you’re trying to size a trapped-ball style chastity device even if you’re going to buy a mass-produced one (like the Holy Trainer or CB-6000):

  • Flaccid penis length (tube/cage length)
  • Flaccid penis diameter (tube/cage diameter)
  • Circumference of both the penis and testicles combined (A-ring circumference)

You may also need to specify the gap width between the tube and ring but I’ve always left that to the manufacturer’s default and been satisfied. As far as I know, the only plastic device that lets you play with this is the CB-6000. The others are fixed.

In my experience and opinion, erect size is not a thing you have to worry about since the entire purpose of a chastity device is to arrest and defeat an erection. I’ve been asked if this is still the case for someone who’s a “grower” (i.e., their flaccid size is far smaller than their erect size) and my guess is no, but I don’t know for sure. I’d be interested to hear the experiences of others in this regard. My hunch is the difference would have to be really big for the erect size of the penis to be an issue. Chances are, sport, that ain’t you. But every penis is like a snowflake: unique. What’s worked for me or the majority of men may not work for all of them.

Also, with regard to issues of erect size, you won’t be doing yourself any favors if you buy a device with room in it thinking it’ll be better for when your dick tries to get hard. Smaller devices are more comfortable than larger ones (as unintuitive as that sounds). If you give the penis a little room to grow inside the device you will experience more pain and discomfort than otherwise, based on my experience. Therefore, you want to determine the normal size of your penis when it’s flaccid and size the device to that.

The thing every owner of a penis knows is that they’re all over the place with regard to size. They shrink up and they plump out (even when you’re not turned on) and can be any size in between. The same goes with scrotums. They’re constantly moving around (seriously, just sit and watch them someday). It is their function, after all, to maintain the temperature of the testes the best they can and that means pulling them closer or letting them hang farther away from your core body heat. Also, some men are “high and tight” in that their scrotums don’t hang down very far at all even when they’re at their most relaxed. Wearing a device is more difficult for these guys, especially at first. Over time and with extended wear, a chastity device will actually stretch a scrotum a bit and loosen that skin up, but it takes a while.

But anyway, as I said, “normal” flaccid size is what you’re looking for. This means a few things. First and most important is to take several measurements over time and at different times. I’d recommend something like 10 or 12 over a few days. Second, try your hardest not to think about what you’re doing. You’re measuring for something that very likely turns you the fuck on so watch Old Yeller or pay your taxes of something beforehand to get your mind off the topic entirely. Otherwise, you know what will happen. Bottom line, nobody knows your penis as well as you do. You know when it’s smaller or larger than normal. If you’re still unsure, err on the short side. If this is a problem for your ego…I can’t help you with that.

Different manufactures use different methods of measuring so make sure you communicate how you did it to them at the time you order. Mature Metal, for example, says you should measure the bottom of the penis. Typically, the penis is measured from the top (at least in my opinion) at the point where its shaft meets your’ pelvis down to the tip. Simple enough.

Most manufacturers want to know the diameter of the penis shaft when ordering. You can eyeball this from above with a ruler but, since penises can sometimes be thicker vertically than they are horizontally, a more accurate way to measure it would be to find diameter from circumference. This can be done a couple different ways. One simple method is to wrap a length of string around it and then measure that against a ruler or tape measure. Alternatively, if you have a tailor’s-style tape measure, you could use that. Once you have the circumference you can find your shaft’s diameter by dividing it by our magical friend π (3.14).

The string method is probably the simplest way to find the total circumference of the entire package though a tailor’s tape is also workable. Mature Metal offers sizing rings to help determine the A-ring size, though remember you’re not sizing a cock ring. Cock rings need to accommodate a full erection and chastity devices don’t necessarily. Initially, I wore a ring that was too big because I sized myself after wearing it all the time, even when I woke up with a raging morning erection.

It’s also worth noting that I’ve found the size A-ring your body can tolerate will change over time, especially during the early days. When first starting out, I discovered I needed a ring that was 2″ (50mm) in diameter. The one I spend most of my time in now is just over 1.5″ (40mm). That’s a huge size swing but it didn’t happen over night. I wore a 45mm ring for several months before moving to 40mm. I think the perfect size for me is actually right now about 42mm. Yes, two little millimeters makes a big difference. What I’m getting at here is you may want to consider ordering two rings up front.

Note that significant changes in your weight or fitness level will also impact the size ring you wear. I’ve needed a slightly larger ring after becoming more active (even though that resulted in weight loss).

The other thing to consider when sizing for an A-ring is the material the device will be made of. Metal is heavier, of course, and I’ve found a ring that fits well when it’s made of lighter plastic will feel too big when used for a metal device.

Another thing I can say about A-rings is they’ll be more comfortable if oval-shaped (sometimes called “anatomically shaped”). It leaves more room for the spermatic cords and vas deferens and other associated plumbing. Constriction of these is the leading cause of pain while in chastity, I’ve found.

Eventually, what you’re looking for is a ring that is snug, but not too tight. You should be able to get your little finger under it when flaccid. When hard, as long as your balls aren’t turning purple and getting cold, it’s not too small. If you’re experiencing testicular pain like a mild version of getting kicked in the balls, it’s probably a little too small (or round). Perfect world, your balls don’t hurt or turn blue (though they may turn a darker color red) but it’s still snug. If the device hangs too low or you can get your fingers through when hard, it’s too big. If your balls pop though when flaccid, it’s also too big (remember, “trapped-ball”). Yes, this is complicated stuff, but there’s a lot of complicated plumbing down there and sensitive tissue.

Of course, all this precise measuring is only really necessary when ordering custom. I DO NOT recommend anyone start out with chastity that way. First thing you should do is buy a plastic device. I recommend the Holy Trainer at the moment but the CB-6000 is also popular for some reason. Get the device that best fits your proportions. In the case of the tube, err on the short side, and in the case of the ring, err slightly larger.

It’s entirely possible you still have questions after all this or comments from your own experience. If so, please feel free to leave a comment below.

31 thoughts on “How to measure for a male chastity device

  1. In terms of tube length and being a “grower”, I am pretty small when flaccid and sort of just over average when erect, length and thickness. I use the smallest tube I can get e.g. CB6000S, the smaller tubes for the Holy Trainer and for the Dickcage. I find the most important thing is to fill the tube when flaccid. And when really flaccid, I don’t even fill the CB6000S. Erections are better (less uncomfortable) for me when stopped when I am smaller. So I would do the same, work from flaccid size when looking at size of tube.

    1. I have a question that fits the theme. My flaccid penis is about 7 to 8cm long. It grows to ~20cm in erect state. That as a basis.
      Now I want to buy a HolyTrainer. Prefer the little one, because I want to make sure that I do not even begin to get an erection. For my penis measurements: is it smarter to buy a small HolyTrainer, or to better buy the larger one?

      1. The rule of thumb for most guys is to match the length of your flaccid size, but most guys aren’t over 7″ long hard. I wish I knew what you should do. If it were me, I’d try the small one. Your bigger issue will be ring size, I suspect.

      2. HI Luke,

        I’m about the same size as you flaccid and erect. I’m also uncut. I have the larger HT2 with a 40mm ring. Most of the time, it seems that I fill in the cage, however within a while/being completely occupied with something else, I’ve noted that my dick shrinks even more and I don’t fill in the entire length. I’m confident that this small amount of room causes a problem.

        After wearing it continuously for week, I’ve had a lot of sleepless nights. I’ve noticed that when erections start and the head begins to swell, it pulls back into the cage and then gets stuck just outside of the moulded bulge for the glans. This is when it’s allowed to get too hard, the cage pulls away from the body, then the ring is pulls hard on the ball sack.

        The 40mm ring is comfortable during the day and most of the night – I contemplated getting smaller or larger to help with the ball pain/sliding, but realized that this ‘sliding’ and ‘pain’ was caused by an erection and it being able to slide halfway out of the cage.

        Therefore, I think the shorter cage would be better. If you look at Mature Metal’s recommendations etc, they suggest a cage that’s shorter than flaccid length to prevent even the beginning of an erection so that the head is pressed up against the end of the cage. I think the same logic should apply here for the HT2.

        Did you end up buying one? How did it go? Are you cut or uncut too?


  2. Iam now in the CB6000s. Iam all from 4 to 7 cm in flacid, most of the time 5,5. I have measured as you have been describing Thumper. Iam going to buy a Looker02 without the plug. My wife and mistress likes to see me trying fill out the gage, she likes to see that my dick gets a little hard and cant get out. What should I order in total leanght?

  3. My dilemma is, that I talked to Dietmar (did not tell him about my wifes desire, only asked for his opiniun in the total leangth) He said 5.5 or 6 cm for the most snug and comfortable use) but I also want to forfill my mistress likes? What leangth should I choose? And is it very stupid to have a too biig Looker02. As for this moment I actually likes to feel that my dick can get a little hard, and it can in the cb6000s, but I also think that 9cm of steelgage will be too much: Iam new in this and frustrated.

  4. You have a great guide here.

    I have a foreskin which adds to my length when flaccid. I’m looking to get a jail bird from MM. Do i measure my length. Do i measure my length as the whole of my penis including added foreskin length or measure to the actual head of my penis if I didn’t have a foreskin. the difference is 3/42 to 1″

    1. Hi Sam,
      Apologies for joining this conversation, but am currently in exactly the same scenario of looking at the Jail Bird and likewise am uncut. When measuring I’m the same and adds between 3/4″ to 1″ to my length. Did you order the Jail bird and if so which measurements did you use and can you offer any guidance with hindsight please? I worry if I go for penis head length that’s a fair amount of skin to bunch up/stick out the end but don’t want to go too big and have too much growing room??

  5. Question on sizing .
    I have the rings from mature metal.
    I’m fine with 11/2″ or 1 5/8″ during the day – they fit the description of how tight they should be. Fit great, nice and secure. No problem. However, I’ve tried sleeping with only the ring, and it wakes me up in pain when I get an erection. My question: will the assembled unit (ring & cage) prevent this from being a problem by preventing the erection in the first place? Or do need a larger ring? (I’ve tried a larger size and it feels loose.)

    1. Yes, a ring that goes with a tube worn by itself will feel WAY too small when erect. That’s my experience, anyway. You need to wear the whole package to really figure out the sizing.

  6. I am interested in getting a 3d printed cage the same one you reviewed.

    The A ring is not round and looks more like a collar with two different sizes as it starts wide and gets smaller.

    There is no information on how to measure for this. The design looks very natural and ergonomic.
    I need help before purchase.

  7. I have an interesting problem that I haven’t found the solution to, yet. First, some background:
    I have the HTv2 w/50mm ring (There’s no way I could slip out of this. I have large testicles, and a large sac.). I am overweight (230lbs) and a “grower”. When completely soft, I’m probably about 3-5cm. When hard, about 15-18cm. A big difference. In fact, when I’m hard, the HTv2 gets pushed out quite far from my body (maybe 7-8cm). Since I have a large stretchy sac, there’s not much to stop it. Anyway… That’s the background, now for the problem.

    In the morning, I have a hard time pissing. Especially if I have consumed too much liquid before bed. Things swell up so much that the tube crimps my urethra closed so tightly that releasing my bladder doesn’t do anything. When I tighten up again, piss shoots out pretty aggressively. I have to do this 3 or 4 times, while carefully manipulating the cage to find the right position to get enough out to get soft enough to let things “flow”.

    I’m trying to figure out if this is a problem with the size of the HTv2 tube, or something else? I currently use the “stocking method” to try to get everything into the tube. I’m wondering if there’s just so much packed in there when I’m growing that there’s too much pressure? I used to use a little Johnson’s baby lotion, but that didn’t get everything into the tube (especially the underside, which would just bunch up between the tube and the sac). Also, I was concerned about the moisture, thinking it would be more hygenic without any added stuff in there.

    I’m not sure what the right solution is. I’m thinking I need a wider (and possibly shorter) tube, but since HT doesn’t make anything wider, I guess that would mean going custom. Which is a shame, because otherwise, I find the HT device very comfortable and discrete.

    Any suggestions / experience you can share?

    1. I have that issue occasionally, as well. Maybe 2-3 times a month is all. For me, I think it’s a simple matter of sometimes things getting into a position so that when everything firms up it clamps the urethra shut. That means I really have to flex to get the piss out and it shoots out in these intense streams (that can even burn) until the fucking hard on goes down enough.

      To me, it sounds like a girth issue. You say what your length is (good for you) but don’t mention circumference. Chances are you’re trying to stuff too much into too tight a space which, on the one hand, sounds hot as fuck to me, but on the other, would present issues like you describe in the wee (get it?) hours of the morning.

      I think you’re right. If this is too much of an issue to deal with, you’re probably going to have to get something custom made. Belle’s Steelheart has a wider and more round tube than the HTv2 which, besides the penis just being smaller than yours all around, makes clamping issues such as you describe less likely.

      1. Damn.. Fast reply. 🙂

        I haven’t actually measured the circumference, but I will do so when time permits. If I guessed, I’d say somewhere around 12-14cm?

        It’s not an “occasionally” for me. It’s an every morning that I wear it overnight.

        Also, when I get a strong nocturnal erection, sometimes I get a “burning” sensation. The last time that happened, I had to take the cage off, and I had two angry dark red bumps right where the vent holes in the tube are.

        goes to look into the steelheart 🙂

      2. Yeah, you’re about an inch bigger around than me. The HT tube is designed for closer to average and you’re over that, sound like. I think if you want to keep up with enforced chastity you’re going to need to go custom.

  8. I just got my Steelworxx L2, what an amazing device 🙂 As you have mentioned on this blog you have one too thus I wanted to ask you about how it fits on you. Does the tip of your penis always touch the dome?
    For me there’s a gap sometimes; I’d say maybe 5mm – 10mm at the very most. 90% of the time my penis touches the dome. Do you experience the same?
    What’s you your recommendation? Should I send it back and get it shortened?

    1. That sounds perfectly normal. Penises shrink and grow all day long. I don’t always totally fill the cage of the L02 but usually do like you.

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