Just put into a chastity device though...

I’m curious about the experience of wearing it. I picked up a Holy Trainer with the medium ring, which matched well with the size on my CB knockoff. It’s largely comfortable; my testicles are slightly red, but there’s no real pain unless something else aggravates them (like sitting incorrectly). The device doesn’t feel any colder than the rest of me—I’d just stepped out of a hot shower so most of my body felt cool to the touch anyway. Also, I have some fitness in the sac that isn’t very noticeable at all. When I first got it, I wore it for nearly a day before taking it off and didn’t experience any significant pain, except for one instance when I tried getting an erection, which wasn’t too bad either. Is this normal or just something to get used to? Or is the fit poor? Right now, as I sit here wearing it, I can barely feel it (maybe only 5% awareness), though I suspect that’s because thinking about writing makes me more conscious of it.

That sounds good to me. The key points are that nothing is pinching and you aren't having things 'pop out.' All of MsM's new devices tend to feel a bit awkward initially. Her latest model, the Contender, is intentionally small so it remains noticeable and never quite 100% comfortable; this keeps reminding me that MsM prioritizes her control over my cock and balls more than my comfort. Anyway, I digress—yours seems fine.