Anal sex most often refers to the sex act involving insertion of the penis into the anus of a sex partner.[1] The term anal sex can also sometimes include other sexual acts involving the anus, including pegging, anal–oral sex, fingering, and object insertion. A 2009 study of American college undergraduates, the large majority heterosexual, found that one in four reported having had anal sex,[2] while the figures for the general population range between thirty and forty percent.
Though anal sex is pleasurable for many people, and some may reach orgasm (through stimulation of the prostate in men, and clitoral and G-Spot leg stimulation in women),[3] others find it painful, in some cases extremely so.[4][5] Some women rate the practice among their least favorite sexual activities because of the pain or discomfort involved. Of the men who receive anal sex, between a tenth and a quarter always find it painful, and almost two thirds rate pain on being penetrated as their most frequent sexual problem. Psychological factors, as well as technique, were found to play a role in the experience of pain during anal sex.[6] As the rectal mucous membrane provides little natural lubrication, a lubricant is generally used when penetrating the anus.[7]
Anal sex is considered a high-risk sexual practice, and unprotected anal sex is the riskiest of all forms of sexual intercourse.[8] The hazards are due to the vulnerability of the tissues, as the penetration of the anus may cause tearing and bleeding of the soft tissues,[9] and can damage the sphincter muscles, causing incontinence and anal prolapse. It is also due to the high concentration of disease causing organisms in the anus and the introduction of pathogens during the sex act itself, exposing the participants to a spectrum of contagious diseases. Pegging, involving the use of a harness and anal penetration by a dildo or other sex toy, can involve fewer risks of damage and disease. Some authorities judge that all anal sex is unsafe, due to the high rates of condom failure, including those brands that claim to be specially strengthened.