Chastity and orgasm denial discussion

My Wife / KH / Goddess and I have tried out all kinds of cages over the years: metal, plastic, silicone, cheap ones, expensive ones; in various shapes and sizes and even adjustable like the early CB-2000 with spacers and rings. My issue isn’t so much about being able to pull-out-the-back but rather my testicles slipping back through the rear ring. Once that occurs, first of all I find it painful (not a good look) and it is effectively possible to just pull the entire cage off. The first time it happens to me it sort of ruins that particular cage - since I know it is not secure. It has actually happened a number of times during the night when I guess I am relaxed, warm and asleep and I don’t even know about it at the time. I have experimented with different size back rings, from 45mm to 50mm. 45mm seems too small for comfortable long-term use and 50mm a bit too loose: although the ergonomically shaped back-rings also make a difference. Although it’s an issue with all shapes and sizes. I used to think that the closeness of the back ring to the cage itself was the key factor: the amount of room to squeeze back through but now I’m not so sure. Is this a problem for other people and has anyone found a way or a cage to solve the problem?