Cock ring
Overview
A cock ring, or cockring, is a ring that is placed around a man's penis
Human penis
The human penis is an external sexual organ of male humans. It is a reproductive, intromittent organ that additionally serves as the urinal duct.-Parts:...

, usually at the base, primarily to slow the flow of blood from the erect penile tissue, thus maintaining erection
Erection
Penile erection is a physiological phenomenon where the penis becomes enlarged and firm. Penile erection is the result of a complex interaction of psychological, neural, vascular and endocrine factors, and is usually, though not exclusively, associated with sexual arousal...

 for a much longer period of time.

Cock rings can be worn around just the penis or both the penis and scrotum
Scrotum
In some male mammals the scrotum is a dual-chambered protuberance of skin and muscle containing the testicles and divided by a septum. It is an extension of the perineum, and is located between the penis and anus. In humans and some other mammals, the base of the scrotum becomes covered with curly...

, or just the scrotum alone, though this is usually called a testicle cuff. Rings can be made of a variety of different materials, most commonly leather, rubber, or silicone, though nylon and metal are also used either as the main component or part of the closure.

The term cock ring is sometimes used as a synonym for a Prince Albert piercing
Prince Albert piercing
For other uses of "Prince Albert", see Prince Albert The Prince Albert is one of the more common male genital piercings...

, a piercing of the penis that is usually, though not always, a metal ring.

When used in cases of erectile dysfunction they are known by various names such as "erection ring", "tension ring" (with context making their purpose clear), etc.
A man may wear an erection ring because he has erectile dysfunction
Erectile dysfunction
Erectile dysfunction is sexual dysfunction characterized by the inability to develop or maintain an erection of the penis during sexual performance....

 (ED) or hyperfunction.
 
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