Anal Sex Anal Sex is stimulation of the anus during sexual activity.
Anal sex can be the primary form of sexual activity or it can accompany other types of stimulation.
Others use the tongue in a similar fashion for oral stimulation. Anal intercourse is the insertion of a man's penis into his partner's rectum. Although anal sex is often thought of as a strictly homosexual activity, many heterosexual couples enjoy it too. Anal penetration can be pleasurable, but it can also be a source of physical discomfort. The muscle on the outside of the rectum, called the anal sphincter, ordinarily tightens if stimulated, which means that attempts at insertion of the penis, or even a finger, may be uncomfortable even if done slowly and gently.