Once in awhile it does happen.

i just got a few different kinds. i have tried them around the penis, around the balls and penis, and they seem to make me more and more sensitive, that i barely enter my wife a few times and explode. not a good thing. i have also tried a few non-sensitizing creams, and they seem to do the same thing. one time i didnt use anything and lasted much longer than those times, but not along time. this is why i tried these rings out, to see if they could help me. but honestly, i think they work differently on everyone. i am not circumcised, so maybe its different for me. There is a cream that i ran out of that is called X-scream that gets alittle hot when you use it and that seem to help me not get as sensitive and last alot longer, guess i will hunt some of that stuff down.

This is my experience as well.

Hubby has started to wear one and while he does sometimes cum faster, he can stand tall longer. when not using one once he cums we have to wait a bit befor he gets hard again, recently I have spent the wait time beating him with various toys but i do enjoy him cumming then being able to keep going for a long while when wearing the ring

Same. Almost always makes me cum quicker. Without a cockring I have trouble getting there, and it can lead to "marathon sex" longest was 10 hours with partner and bathroom breaks, average 20-30 minutes with partner. Cock ring longest ~20 minutes. Average 10-15.