One of our faves is this , which comes complete with a ball loop and a built-in bullet vibe and also features textured nodules for the ultimate in stimulation in all the right places.
Cock rings come in many shapes and sizes, but most involve a loop that is placed around the base of the penis and sometimes testicles , and the tightness on the shaft creates a longer-lasting, harder erection.
The cock ring is very stretchy and you can should have no trouble getting it on.