Anal sex most often refers to the sex act involving insertion of the penis into the rectum. The term anal sex can also sometimes include other sexual acts involving the anus, including but not limited to anilingus and fingering.
It is a form of sexual behavior considered to be comparatively high in risk, due to the vulnerability of the tissues and the septic nature of the anus. As the rectal mucosa provides little natural lubrication, a personal lubricant is most often required or preferred when penetrating the anus.
In other cases, first anal intercourse is conceived of as ending a separate virginity from first vaginal intercourse, with varying degrees of seriousness. In a Rolling Stone interview, comedian Sarah Silverman joked: "I didn't lose my virginity until I was twenty-six. Nineteen vaginally, but twenty-six what my boyfriend calls 'the real way.'
In 2005, a survey conducted by the Centers for Disease Control determined that the incidence of anal relations in the heterosexual population is on the increase. The survey showed that 40 percent of men and 35 percent of women between 25 and 44 had engaged in heterosexual anal sex; in 1992 a similar survey found that only 25.6 percent of men 18 to 59 and 20.4 percent of women 18 to 59 had. One theory about the increase in anal relations amongst heterosexual couples is that "as gay culture has become more acceptable, especially among a younger generation, traditionally gay practices, like anal sex, are becoming more common in the rest of society." .
A 2001 French survey of five hundred female respondents concluded that a total of 29% had practiced anal sex, though only one third of these claimed to have enjoyed the experience. In contrast, in a 1999 South Korean survey of 586 women, only 3.5% of respondents reported having had anal sex.
Figures for the prevalence of sexual behavior can fluctuate over time. Edward O. Laumann's 1992 survey, reported in The Social Organization of Sexuality: Sexual Practices in the United States found that about 20% of heterosexuals have engaged in anal sex. Sex researcher Alfred Kinsey, working in the 1940s, had found that number to be closer to 40% at the time. More recently, a researcher from the University of British Columbia in 2005 put the number of heterosexuals who have practiced anal sex at between 30% and 50%.
According to Columbia University's health website, Go Ask Alice!: "Studies indicate that about 25 percent of heterosexual couples have had anal sex at least once, and 10 percent regularly have anal penetration.
In the receiving partner, being penetrated can produce a pleasurable sensation due to the inserted penis rubbing or brushing against the prostate through the anal wall. Penetration can be painful if the bottom partner's anus is not properly lubricated.
Stimulation of the prostate gland can result in pleasurable sensations and can lead to a distinct type of orgasm in some cases. The prostate is located next to the rectum and is the larger, more developed male homologue to the Skene's glands, which are believed to be connected to the female "G-spot". The Skene's glands are sometimes referred to as the "female prostate", and which are located around the urethra and can be felt through the wall of the vagina.
In the 1950s in the United Kingdom, it was thought that about fifteen percent of male homosexuals practiced the method. The Gay Urban Men's Study (P.I. Stall, UCSF) and the Young Men's Study (YMS, PI Osmond/Catania, UCSF), indicate that 50% of men surveyed engage in anal sex. The Laumann study claims that 80% of gay men practice it, while the remaining 20% never engage in it at all.
A survey conducted from 1994 to 1997 in San Francisco by the Stop AIDS Project indicated that over the course of the study, among men who have sex with men, the proportion engaging in anal sex increased from 57.6% to 61.2%.
Anal sex exposes participants to two principal dangers: infections, due to the high number of infectious microorganisms not found elsewhere on the body, and physical damage to the anus and the rectum due to their vulnerability.
Recent reports have documented that risky behavior is on the rise among men who have sex with men. Likewise, among men who have sex with women, a 1992 study of socially and sexually active Puerto Rican men indicated that of the more than 40% who reported having anal sex with women, very few had used condoms. Among gay men, anal sex without the use of a condom is referred to as barebacking.
Among the diseases with which anal sex is associated are HIV, human papilloma virus (HPV) (which can increase risk for anal cancer) typhoid fever and various diseases associated with the infectious nature of fecal matter or sexual intercourse in general. Among these are: amoebiasis; chlamydia; cryptosporidiosis; E. coli infections; giardiasis; gonorrhea; hepatitis A; hepatitis B; hepatitis C; herpes simplex; human papillomavirus; Kaposi's sarcoma-associated herpesvirus (HHV-8); lymphogranuloma venereum; pubic lice; salmonellosis; shigella; syphilis; tuberculosis.
The high concentration of white blood cells around the rectum, together with the risk of cuts to the rectum and that one of the functions of the rectum is to absorb fluid, increases the risk of HIV transmission because the HIV retrovirus reproduces within the immune system's T-cells/CD4 cells. Use of condoms and other precautions are a medically recommended way to lessen risk of infections. Unprotected receptive anal sex is the most risky sexual behavior in terms of HIV transmission.
Most cases of anal cancer are related to infection with the human papilloma virus. The incidence of the disease has jumped 160% in men and 78% in women in the last thirty years, according to a 2004 American study. The increase is attributed to changing trends in sexual behavior and tobacco use. Current use of tobacco increased the incidence of anal cancer four-fold, while a history of multiple sex partners (fifteen or more) or receptive anal sex increased the incidence seven-fold.
Physical damage to the rectum and anus can manifest as generalized ano-rectal trauma, hemorrhoids, anal fissures, and rectal prolapse. An insufficient amount of lubricant can make it especially painful or injurious. Damage is more likely if intercourse is forcible or aggressive, if alcohol or other drugs have dulled sensitivity, if communication is poor, or if technique is clumsy.
A 1997 study published in the American Journal of Gastroenterology found no difference in levels of incontinence between homosexual men who engaged in anal sex and heterosexual men who did not, and severely criticised an earlier 1993 study published in the Journal of the Royal Society of Medicine which had found that fourteen out of a sample of forty men receiving anal intercourse experienced episodes of frequent anal incontinence for its inclusion of flatulence in its definition of incontinence.
Dr. Jack Morin recommended kegel exercises to prevent loss of muscle tone from anal fisting or insertion of large objects in a presentation of clinical aspects of anal sexuality, delivered at the 1998 joint conference of the Society for the Scientific Study of Sexuality and the American Association of Sex Educators. He added, however, that he had never personally observed "loosening" in any of his patients.
Historically, a number of cultures have recorded the practice of anal intercourse between men. The males who participated in such relationships often did not do so exclusively, as participation in these relationships between men did not preclude sex with women. Such relations have also been documented as taking place in houses of prostitution, which provided youths or young men.
The term "Greek love" has long been used to refer to the practice, and in modern times, "doing it the Greek way" is sometimes used as slang for anal sex. However, homosexual anal sex was far from a universally accepted practice in Ancient Greece. It was the target of jokes in surviving comedies; Aristophanes mockingly alludes to the practice, claiming that "Most citizens are europroktoi (wide-arsed) now. While pedagogic pederasty was an essential element in the education of male youths, these relationships, at least in Athens and Sparta, were expected to steer clear of penetrative sex of any kind. There are very few works of pottery or other art that display anal sex between older men and boys, let alone with adult men. Most such works depict fondling or intercrural sex, which was not condemned for violating and feminizing the boys. Other sources make it clear that the practice was criticized as shameful, and seen as a form of hubris.
In later Roman age Greek poetry, anal sex became a common topos, represented as taking place with "eligible" youths: those who had attained the proper age but had not yet become adults. Seducing children into the practice was considered very shameful for the adult, and having such relations with a male who was no longer adolescent was considered more shameful for the young male than for the one mounting him. Greek courtesans, or hetaerae, are said to have frequently practiced heterosexual anal intercourse as a means of preventing pregnancy. The acceptability of anal sex thus varied with the time-period and the location, as Ancient Greece spanned a long time and stretched over three continents and two major seas.
For a male citizen to take the passive (or receptive) role in anal intercourse was condemned in Rome as an act of impudicitia (immodesty or unchastity). Free men, however, frequently took the active role with a young slave, known as a catamite or puer delicatus. In fact the Romans thought of anal sex as something specifically "Greek," although Roman men often availed themselves of their own slaves or others in this way.
In Japan, records (including detailed shunga) show that at least some men in relationships with other men did engage in penetrative anal intercourse.
Evidence suggestive of widespread heterosexual anal intercourse in a pre-modern culture can be found in the erotic vases, or stirrup-spout pots, made by the Moche people of Peru; in a survey of a collection of these pots, it was found that 31 percent of them depicted heterosexual anal intercourse, more by far than any other sex act. Moche pottery of this type belonged to the world of the dead, which was believed to be a reversal of life. Thus the reverse of common practices was often portrayed. The Larco Museum houses an Erotic Gallery in which this pottery is showcased.
The 19th century anthropologist Richard Francis Burton has theorized that there is a geographical Sotadic zone wherein penetrative intercourse between men is particularly prevalent and accepted; moreover he was one of the first writers to advance the premise that such an orientation is biologically determined.
In many Western countries, anal sex has generally been taboo since the Middle Ages when heretical movements were sometimes attacked by accusations that their members practised anal sex among themselves. At that time the mainstream Christian clergy was not celibate, but the highest orders of some heretical sects were, leading to rumours that their celibacy was a sign of their attraction to members of the same sex. The term buggery originated in medieval Europe as an insult used to describe the rumoured same-sex sexual practices of the heretics from a sect originating in Bulgaria, where its followers were called bogomils; when they spread out of the country they were called buggres (from the ethnonym Bulgars). Another term for the practice, more archaic, is "pedicate" from the Latin pedicare, with the same meaning.
While men who engaged in homosexual relationships were generally suspected of engaging in anal sex, many such individuals did not. Among these, in recent times, have been André Gide, who for that reason was said to have been the pope of a religion to which he did not belong; and Noel Coward, who had a horror of disease, and asserted when young that "I'd never do anything - well the disgusting thing they do - because I know I could get something wrong with me.
This prohibition of the Abrahamic religions against anal sex has been promulgated under the rubric of "sodomy," which includes various other transgressions of a sexual nature, whether with men, women or animals. This idea is vividly brought to life in the popular interpretation of the story of Sodom, where the people were prone to sexual immorality, and as a result were destroyed. There are conflicting views as to why Sodom was destroyed.
Orthodox Judaism teaches that sodomy is homosexual anal sex, and is a sin and toevah (abomination), based on the Bible passages Leviticus 18:22 and 20:13; the injunction "Do not lie with a man the lyings of a woman; it is abhorrent." has led rabbinical scholars to conclude "these verses to prohibit anal sex between men without any exception." The Conservative, Reform and Reconstructionist branches of Judaism are accepting of homosexuality, but less so of sodomy.
However, Judaism permits heterosexual anal sex.
In Christian countries it has often been referred to euphemistically as the peccatum contra naturam (the sin against nature, after Thomas Aquinas) or Sodomitica luxuria (sodomitical lusts, in one of Charlemagne's ordinances), or peccatum illud horribile, inter christianos non nominandum (that horrible sin that among Christians is not to be named). Although some Christians may disapprove of anal sex, others believe it to be acceptable.
Liwat, or the sin of Lot's people, is officially prohibited by most Islamic sects. There are parts of the Qur'an which talk about smiting on Sodom and Gomorrah, and this is thought to be a reference to unnatural sex, and so there are hadith and Islamic laws which prohibit it. Practitioners of anal relations are called luti and are seen as criminals in the same way that a thief is a criminal, meaning that they are giving in to a universal temptation. Liwat with a woman is known as lesser liwat and with a man as greater liwat.