Holy Trainer v2 Issue

Hi all, I have a question for anyone who has an HTv2. I recently got mine—the small tube paired with the 40mm diameter ring. After wearing it for several hours, I started feeling pain and burning in my testicles. Is this because the ring is too tight or perhaps the tube isn’t long enough? I feel like the length of the tube is spot on since there’s no slipping around, so I suspect the base ring might be squeezing a bit hard. Would switching to the 45mm diameter ring help, or should I go even bigger? My main worry with going too large is that I might slip out. However, my wife insists on all-day wear (which I’m happy to do), but it gets quite painful after some time. Has anyone else dealt with this burning feeling? What are your thoughts? Thanks in advance for any advice!