Chastity and orgasm denial discussion

Hello, I’ve been testing out my new device to ensure a snug fit and noticed that when he gets swelled up, not much change occurs. I think it’s great lol. The cage points outward and is slightly pushed away from his body, but the ring doesn’t seem to slide down, so it looks good. However, after being aroused for some time, his scrotum starts to darken in color; they might even get a bit larger too. It gets close to the shade of a firm shaft when you squeeze its base. So it seems that circulation is restricted by his erection. Does this indicate the base ring is too tight and we should try one that fits better while erect, or that the ring is too big and allowing him to swell up too much? Thanks for the advice