A cock ring or cockring is a ring worn around the penis, usually at the base. The primary purpose of wearing a cock ring is to restrict the flow of blood from the erect penis in order to produce a stronger erection or to maintain an erection for a longer period of time. Genital adornment is another purpose, as is repositioning the genitals to provide an enhanced appearance.
Cock rings are also called C rings, penis rings or shaft rings. When used in cases of erectile dysfunction (ED), they are known by various other names, such as erection rings and tension rings.
Cock rings worn just behind the corona of the glans of the penis are known as glans rings, head rings or cock crowns.
A ring that is worn around the penis and scrotum is also usually called a cock ring, but is sometimes referred to as a cock and ball ring.
Rings that are worn just round the scrotum, in order to hold the testicles, are usually called testicle cuffs or ball stretchers.