Chastity and orgasm denial discussion

Before settling on which device to purchase, I struggled greatly with taking accurate measurements. Suddenly, it struck me that among my other bondage toys sat a ring with a two-inch diameter. I have been—and still am—able to wear this ring without discomfort. … Maybe even too much comfort. One morning after sleeping in it, I discovered the ring had slipped off on its own. If I were to use a similar Holy Trainer (I estimate around 50 mm), can I reasonably expect it might also slide out?