There is no single way of wearing a cock ring because there is no single design or style. To begin with, they just don't come in metal. You can also find them in velcro or in some kind of elasticized material, stretchy enough to make them easy to get on. Most of mine are metal, because I think they feel and look more sexy, ensure a firmer erection and are awesome for extended fucking.
Some cock rings are designed simply to fit tightly around the base of the cock. Others go around both the cock and balls. I like my double loop style where one ring goes fairly tightly aroiund the base of my cock, and the other around the cock and balls.
I also have a triple ring, alias a three-ring-circus, which I think causes awesome sensations, but it can be a challenge to get on. One ring goes around the base of my cock, the second around my cock and balls and the third around my balls alone. (See the photo in the previous message.) It's this third ring around the balls that's important because it prevents my balls from receding into my body, which normally happens during increasing sexual excitement. It's this that extends the length of a fuck and triggers different sensations that I have trouble even describing. what I do know is that when I come my load seems to shoot out forever.
Cock rings aren't that pricey — so experiment! I got one in Germany that isn't intended for fucking but to improve the size of my bulge when I'm wearing tight jeans or on the beach in Speedos or a thong. It keeps my cock heading for an erection — but not going all the way