Introductions discussion

Hello, I am new to chastity devices. I purchased a CB 6000s model. We currently use it for short-term fun. My wife is worried about the device hurting me and what would happen if a medical emergency arose, leaving little time or physical ability to remove it due to that emergency. I hope to transition to long-term lock up, but as you might guess from my previous statement, my wife is somewhat vanilla. For eleven years, I have tried to get her to take the lead in our relationship and really hope one day she will make me watch as she cuckolds me and then force me to clean her up. That is another story for another time (hopefully not another 11 years). What I wanted to ask now was how to solve a problem with my device. It fails to stay on after being locked. I use the smallest ring possible, but it seems I lack enough room behind my ball sac for the ring to sit and remain secure. After a few hours, the ring slides over the balls and falls off while the cage remains attached and lock is engaged. I have used cock rings before and had the same issue with them. Does anyone else have or have had this problem and can offer suggestions? Perhaps I need a different device, but given my past experience with cock rings, I am not sure that is truly the cause. I believe it is more about my physical anatomy. Long-term chastity is out of the question unless I find a way to keep the ring in place. Thanks.