Cock-rings are designed to help maintain an erection. They can be made of many materials: latex, silicon or metal. However, metal ones can be tricky to remove.
Men have been using cock rings for a long time as sex toys and marital aids. They are primarily a way of helping to keep the penis hard and erect for a longer period of time. Use of a cock ring can be a great alternative method of erection control, without the side effects of expensive pharmaceuticals.
The ring around the penis works by slowing down the flow of blood out of the penis compared to the blood coming in, thereby increasing pressure. For some men a cock ring can help them control premature ejaculation during sex, or to generally prolong love making.
When wearing a cock ring, the penis is not only firmer but less sensitive in general, and therefore a man can better control when he wants to experience orgasm.
Some kinds of ring come with a quick release snap or toggle that can be used to restore normal circulation and sensation to the cock, when the moment is right.
Most cock rings are made of materials like rubber, but you can also get rings made of metal (in various sizes), and leather with snaps to adjust the fit.
Cock Ring Use: Try to make sure you have a cockring that's tight, but not too tight. Remove a cockring if you feel it's cutting off the circulation too much, or if your cock goes strange colors. If you have a cock ring that fits properly, you should be able to come with it on, or remove it easily enough while you have an erection.
Vibrating Cock Rings: The vibrating ring takes the concept further by adding a vibrating bullet to the cock ring. The sensations from the bullet can be felt by both partners, and some have special ticklers for the woman's clitoris or anus.