Cock rings are rings that are designed to fit around the base of an erect penis, restricting the flow of blood from the penis and (theoretically) maintaining erections for longer.
They can come in elasticated or fixed varieties, and can be made from metal, plastic or wood. Some alternative forms also fit around other parts of the penis, including the head or middle of the shaft.
Men have sought to extend their erections almost ever since they started having sexual intercourse. We don't know exactly who had the idea to slip a ring around their cock, or when they did so, but archaeologists have uncovered implements from ancient Rome and Greece that almost certainly did the job.
During China's Jin Dynasty, wealthy men regularly used specially made jade rings to extend their hard-ons, and you can bet that cultures throughout the ages have done something similar.
Generally, penis rings are made from elastic materials like rubber or latex, or harder materials like metal or tougher forms of plastic. There are two major types:
Whichever type you choose, it will act like a valve, allowing blood to flow into a penis (making it erect) but not out of it. As pressure is applied to blood vessels at the base of the penis, blood flow is decreased and the penis becomes "engorged".
The effect varies between guys, but in general cock rings deliver a few minutes of extra hardness, making them a go-to accessory for millions of people.
The benefits of wearing a ring around your cock can be immense. Basically, with more blood in the penis, guys tend to feel more sexual sensitivity, with more intense orgasms. They also report greater stamina, allowing them to satisfy their partners more effectively.
As for safety, there shouldn't be an issue with placing a ring around your cock. After all, they have been used for millennia with no noticeable ill effects.
However, there are some things to remember. Experts recommend using rings for no longer than half an hour at a time.
If you get greedy, there's a chance of sustaining permanent nerve damage, decreasing your penile sensitivity for good. If you are concerned about safety, go for an elasticated ring, as harder varieties tend to cut off more of the bloodflow to the penis.