getting started with my CB6000 on the second day

I picked up my CB6000 yesterday and my wife locked me in almost immediately. I began with the largest ring combined with the biggest spacer, but this configuration left plenty of room; my cock barely filled any space inside the tube. I kept it on like that for about four hours last evening without a problem. I held off wearing it to bed so my skin could get accustomed first. This morning, she put it back on me right away. I stuck with the largest ring but switched down to the second-shortest spacer instead of the biggest one. It felt good until she started teasing me—kissing and pretending to suck—and as I got hard, my cock pressed against the tube walls, trying to push the device off while increasing pressure from the ring on my testicles. After a few minutes in this state, we noticed my balls were turning purple. When not aroused, it was fine though. She removed it quickly, and we put back on the largest ring with its matching spacer, which is what I’m wearing now. Is turning purple a bad sign? Should I keep the biggest ring and spacer for a few days to build tolerance before trying smaller sizes? Any advice would be great.

Thanks