Questions about finding the right fit

I’m still trying to figure out exactly how to pick a device that suits me. Like lots of others, I’m what’s called a “grower,” starting off at about 2” and ending up with a respectable 6-7” once things get going. Of course, for chastity devices the erect length doesn’t matter much, so we can ignore that part. My flaccid penis measures around 2 inches, though how you interpret that number might vary. In emails with Mature Metal—great people to deal with—I was told a device should “fit like a glove.” When I lay my member against a ruler, the measurement from bow to stern comes out to an average of 2.5”. However, when I step into a CB6000S (which is supposed to have an internal length of 2.5”), it feels at least half an inch too short. It seems like loose skin is pooling in the gap, which I keep at the standard 3/8”. The inside diameter doesn’t seem overly tight since it’s the usual 1-3/4”, no skin is bulging through those side vents that don’t do much anyway, and using silicon lube helps my meat move freely into a natural position within the tube.

So for my next device, how should I determine the right fit? I want to avoid the tube being so short that skin pokes out and gets chafed (no enclosed tubes for me), but I still want reasonable snugness. Should I opt for a larger diameter to help pull the gap skin inside? Security isn’t my top worry since we all know escape is possible with enough will, especially given how small and flexible mine is right now. Comfort (and hygiene, hence the open tube) are what matter most. Thanks!

Fit it while flaccid; otherwise that extra room encourages growth and leads to more rubbing and skin irritation. I wear an MM Jailbird, and its design makes cleaning easy while letting the skin breathe well. Talk to MM—they've assisted thousands of men with their chastity setups, so they'll know exactly how to handle your sizing needs. As a side note, because I have a frenum piercing with a captive bead ring plus a second lock, it's hard for me to escape without my keyholder noticing easily. But that’s just my personal preference.

When working with any custom device maker, stick to their specific measurement guidelines. Different makers measure slightly differently. I’d suggest following MM’s advice if that’s the brand you’re buying from these creators have produced thousands of devices and trust in their ability to get the fit right. Most people end up very happy with them.

I’m also a grower, though not quite as much as you described. I measured at 2" completely flaccid, and they subtracted 1/4" from that to give me a cage length of 1 3/4", which has been fantastic! It fits perfectly. Their website states that "you cannot and will not be able to erect in our devices," and they’re right! The most I manage is a bit of swelling, even when stimulated enough to have a minimized or ruined orgasm!