I am sure that I am not the only guy to do this but I sat down to dinner, which was Lasagna my favorite, and was not paying attention and sat on my balls forcing one through the ring. It hurt like heck and I had to keep my cage off for a few hours Who else has sat on their balls when locked? That is why my wife or I carry an emergency key when we go out. Never know when you will need it for an unexpected emergency.
When I wore my jail bird, and was using the bigger ring, I had done that. It didn't hurt all that much but I needed the key to get everything back to normal. Ring was way too loose and my lock that I was using was smaller diameter, so there was play between cage and ring.
My problem is that one testicle is noticeably smaller then the other so I have to split the difference in ring size. I rather have a testicle slip out a few times a year than be uncomfortable.
I had the same thing with my CB2000 When I got my Jailbird I got the ring tighter, too tight in fact so had to get it made a little bigger. Too loose or too tight is not good. Finding the right spot takes some trial and error. Something I think most don't have the patience to do. I know as I've been frustrated a few times from the trials, tribulations and real physical pains.