Penis rings, also referred to as constriction rings or cock rings, are designed to help men keep longer-lasting, firmer erections. Penis rings apply pressure to the genitals, constricting blood flow and keeping blood in the shaft of the penis. They can help with common erectile dysfunctions like difficulty maintaining an erection or premature ejaculation. They can also heighten orgasmic sensation (although some men can't orgasm while the ring is on; both reactions are normal).
A penis ring is slipped down to the base of the penis, generally after you achieve an erection. Some penis rings just encircle the penis, while others go around both the scrotum and the penis. They can be made out of rubber, silicone, metal or leather. It's best to start with an adjustable penis ring.
Vibrating penis rings add extra pleasure for both partners. They have the same benefits as a penis ring, but also include a bullet that sits at the base of the penis, which serves to stimulate the clitoris. Some rings have vibrating mechanisms that sit below the penis as well, to stimulate the testicles.