I'm not a big fan of gear, which is what I'd classify a cockring. I personally find them cumbersome and uncomfortable. But guys have been wearing them for as long as I've been having sex (actually, much much longer, I'm sure), which is now over 30 years. So they must work on lotsa guys to remain so popular.
I have a nice collection of abandoned cockrings in my nightstand drawer, left by various guys, but never feel the urge to wear one, so they're kinda wasted.
I did have one encounter with a guy who had a length of stretchy rubber/latex, about 25 X 3/4". He wrapped it around the base of my dick, then used the remaining portion to stretch and separate my balls. It felt odd at first, but I got used to it quickly. The beauty of this arrangement was that I was able to insert both balls and dick in his hole (after extended handball to open him up). That was a unique experience.