Anal sex (also called anal intercourse) is the sex act in which the penis is inserted into the anus of a sexual partner. The term can also include other sexual acts involving the anus, including pegging, anilingus, fingering, and object insertion.
While anal sex is commonly associated with male homosexuality, research shows not all gay males engage in anal sex and that it is not uncommon inheterosexual relationships. Types of anal sex can also be a part of lesbian sexual practices.
Many people find anal sex pleasurable, and some may reach orgasm — through stimulation of the prostate in men, and clitoral and G-Spot leg stimulation in women. However, many people find it painful as well, sometimes extremely so, which may be primarily due to psychological factors in some cases.
As with most forms of sexual interaction, anal sex participants risk contracting sexually transmitted diseases; anal sex is considered a high-risk sexual practice because of the vulnerability of the anus and rectum. The anal and rectal tissues are delicate and do not provide natural lubrication, so they can easily tear and permit disease transmission, especially if lubricant is not used. Unprotected anal sex is considered the riskiest form of sexual intercourse; authorities such as the WHO issue recommendations for making anal sex safer.
Anatomy and stimulation
The abundance of nerve endings in the anal region and rectum makes anal sex pleasurable for many men and women. “The opening and closing of the anus is controlled by the internal and external sphincter muscles (the most important muscles when engaging in anal sex). The sphincter muscle is a sensitive membrane with many nerve endings and thus the source of pleasure or pain.”
In a male receiving partner, being penetrated can produce a pleasurable sensation due to the inserted penis rubbing or brushing against the prostate (also known as the “male G-Spot”, “P-Spot” or “A-Spot”) through the anal wall. This can result in pleasurable sensations and can lead to an orgasm in some cases. “For some men, prostate stimulation produces an orgasm that they describe as ‘deeper’, more global and intense, longer-lasting, and associated with greater feelings of ecstasy than orgasm elicited by penile stimulation only.” 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).
Research shows that most women (70–80%) achieve orgasm only through direct clitoral stimulation. The clitoris surrounds the vagina somewhat like a horseshoe and its tip or glans alone has more than 8,000 sensory nerve endings, more than any other part of the human body. In addition to nerve endings present within the anus and rectum, women may find anal stimulation pleasurable due to the “legs” of the clitoris which extend along the vaginal lips back to the anus. The Gräfenberg spot, or G-Spot – a small area behind the female pubic bone surrounding the urethra and accessible through the anterior wall of the vagina – is considered to have legs in relation to the clitoris. Besides their accessibility, orgasm by stimulation of the clitoris or G-Spot through anal penetration is made possible because a thin membrane is all that separates the vaginal cavity from the rectal cavity, allowing for indirect stimulation. Only a small percentage of women are able to orgasm from this type of stimulation alone. Direct stimulation of the clitoris, G-Spot, or both, during anal sex can help some women to enjoy the experience and reach orgasm.
In pornography, anal sex is often presented as routine and painless, but according to Go Ask Alice! and other researchers, anal sex occurs “much less frequently” than other sexual behaviors and can be painful if not performed with care. The increase of anal activity among heterosexuals has been linked to the increase in anal pornography, and the association with dominance and taboo make anal sex appealing to people of all sexual orientations. Moreover, the opening of the anus (its sphincter) is usually tighter than a vagina, which can yield greater tactile pleasure for the man via his penis.
While each person’s sphincter muscles react to penetration differently, the anal sphincter in general has delicate tissue that can tear, and the rectal mucous membrane provides insufficient lubrication for sexual penetration. Researchers say adequate lubrication, relaxation, and communication between sexual partners are crucial to avoid pain or damage to the anus. Ensuring that the anal area is clean and the bowel is empty (for both aesthetics and practicality) is also recommended.
Male to female
Some men may enjoy being the insertive partner in anal sex because the anal sphincter is usually tighter than a vagina, which can yield greater tactile pleasure for the man via his penis. The attitude of women towards being the receptive partner in this practice is diverse: while some consider it painful or uncomfortable, others find it pleasurable and some even prefer it to vaginal intercourse. Unlike the clitoris or anus, the vaginal walls “contain relatively few nerve endings, making intense sexual stimulation, pleasure, and orgasm from vaginal-only penetration unlikely” and “it’s generally only the lower third of the vagina that has enough nerve endings to feel any stimulation at all from a penis, finger, toy, or other penetrative object”. Vaginal intercourse may, however, promote a satisfying feeling of fullness or closeness with a sexual partner.
In a study of heterosexual anal sex – (8/2010 (n=214)) – female participants stated that stimulation to multiple erogenous zones simultaneously (the clitoris, the G-Spot, the anus, or other erogenous zones) enabled them to enjoy anal intercourse with much less discomfort compared to anal penetration by itself. When accompanied by one or more of the other stimuli, women were able to orgasm and those who did reported that an orgasm during anal sex is more of a full-body experience than an orgasm from clitoral stimulation alone.
Anal sex is held to carry a very low risk of unwanted pregnancy when not accompanied with vaginal intercourse, as anal intercourse cannot lead to pregnancy unless sperm is somehow transported to the vaginal opening in the process; in some populations, this activity is frequently used as a means of contraception, often in the absence of a condom.
The risk to the woman is greater than the risk to the man during male-to-female anal intercourse. The risk of injury to the receptive partner due to anal intercourse is many times higher than that due to vaginal sex, and the risk of transmission of HIV is higher for anal sex than for vaginal sex. Experts caution couples engaging in this practice to use protection, such as condoms, to stop the transmission of STDs. Additionally, if the man moves from anal sex immediately to vaginal sex without a condom or without changing it, infections can arise in the vagina due to bacteria present within the anus; this also applies to the use of sex toys.
Male-to-female anal sex may be viewed as a way of preserving female virginity because it is non-procreative and does not penetrate the hymen. Among sexually active heterosexuals, the concept of “technical virginity“, which includes anal sex, oral sex and mutual masturbation, is conceived as resting solely on penile-vaginal penetration.
In 1992, a study conducted by the U.S. Centers for Disease Control and Prevention found that only 26% of men 18 to 59 and 20% of women 18 to 59 had engaged in heterosexual anal sex; a similar 2005 survey (also conducted by the U.S. Centers for Disease Control and Prevention) found a rising incidence of anal sex relations in the American heterosexual population. The survey showed that 40% of men and 35% of women between 25 and 44 had engaged in heterosexual anal sex. In terms of overall numbers of survey respondents, seven times as many women as gay men said that they engaged in anal intercourse, with this figure reflecting the larger heterosexual population size. According to a study from the National Survey of Sexual Health and Behavior (NSSHB) that was authored by Dr. Debby Herbenick and other researchers, although anal intercourse is reported by fewer women than other partnered sex behaviors, partnered women in the age groups between 18–49 are significantly more likely to report having anal sex in the past 90 days. As of 2011, this survey provides the most up to date data about anal sex at the population level.
In a 2007 report entitled Prevalence and Correlates of Heterosexual Anal and Oral Sex in Adolescents and Adults in the United States, published in the Journal of Infectious Disease, a national survey of Family Growth found that 34% men and 30% women reported ever participating in heterosexual anal sex. The percentage of participants reporting heterosexual anal sex was significantly higher among 20- to 24-year-olds and peaked among 30- to 34-year-olds. Another survey in, 2008, focused on a much younger demographic of teenagers and young adults, aged 15–21. It found that 16% of 1350 surveyed had had this type of sex in the previous 3 months, with condoms being used 29% of the time. However, given the subject matter, the survey hypothesized the prevalence was probably underestimated.
In 2009, Kimberly R. McBride published a clinical report in The Journal of Sex Research which stated that changing norms may affect the frequency of heterosexual anal sex behaviors and suggests that there is a role for the exotic in the sexual repertoires of some heterosexuals” “[F]or a certain number of heterosexuals, anal intercourse is pleasurable, exciting, and perhaps considered more intimate than vaginal sex…”. McBride and her colleagues investigated the prevalence of non-intercourse anal sex behaviors among a sample of men (n=1,299) and women (n=1,919) compared to anal intercourse experience and found that 51% of men and 43% of women had participated in at least one act of oral–anal sex, manual–anal sex, or anal sex toy use. McBride and Janssen found that the majority of men (n=631) and women (n=856) who reported heterosexual anal intercourse in the past 12 months were in exclusive, monogamous relationships: 69% and 73%, respectively.
Figures for prevalence can vary amongst different demographics, regions, and nationalities. A 2001 French survey of five hundred female respondents concluded that a total of 29% had engaged in this practice, with one third of these confirming to have enjoyed the experience. In contrast, in a 1999 South Korean survey of 586 women, 3.5% of respondents reported having had this type of sex.
Figures for the prevalence of sexual behavior can also 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 had engaged in male-to-female 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 engaged in this practice 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.”
Female to male (pegging)
Pegging is a sexual practice in which a woman penetrates a man’s anus with a strap-on dildo. Advice columnist Dan Savage wrote that he believes all men should try pegging at least once, as it may introduce them to a new enjoyable sexual activity and illuminate them to the receiver’s perspective in sex. A few instructional movies and books have emerged in recent years, including Bend Over Boyfriend, produced by Fatale Media, Inc., and directed by Shar Rednour, SIR Video co-founder. As an accomplished author of numerous sex guides and informational books on various sexual taboos, Violet Blue wrote and released The Adventurous Couple’s Guide to Strap-On Sex in 2007.
The National Institutes of Health (NIH), with information published in the British Medical Journal (BMJ), states that, “There are little published data on how many heterosexual men would like their anus to be sexually stimulated in a heterosexual relationship”, but that, “Anecdotally, it is a substantial number. What data we do have almost all relate to penetrative sexual acts, and the superficial contact of the anal ring with fingers or the tongue is even less well documented but may be assumed to be a common sexual activity for men of all sexual orientations.”
Male to male
Historically, anal sex has been commonly associated with male homosexuality. However, many men who have sex with men do not engage in anal sex. Among men who have anal sex with other men, the insertive partner is called the top and the one being penetrated is called the bottom. Those who enjoy either role are referred to as versatile. Gay men who prefer anal sex may view it as “[their] version of intercourse” and as “the natural apex of sex, a wonderful expression of intimacy, and a great source of pleasure”. Psychologist Walt Odets said, “I think that anal sex has for gay men the same emotional significance that vaginal sex has for heterosexuals”.
Some men who have sex with men prefer to engage in frot or other forms of mutual masturbation because they find it more pleasurable or more affectionate, to preserve technical virginity, or as safe sex alternatives to anal sex, while other frot advocates denounce anal sex as degrading to the receptive partner and unnecessarily risky.
The prevalence of anal sex among homosexual couples in the West has varied over time. Magnus Hirschfeld, in his 1914 work, The Homosexuality of Men and Women, reported the rate of anal sex among homosexual men surveyed to be 8%, the least favored of all the practices documented. Likewise, some scholars state that oral sex and mutual masturbation are more common than anal stimulation among gay men in long-term relationships, and that, in general, anal intercourse is more popular among homosexual male couples than among heterosexual couples, but that “it ranks behind oral sex and mutual masturbation” among both sexual orientations in prevalence.
By the 1950s in the United Kingdom, it was thought that about fifteen percent of male homosexuals had anal sex. More recent studies, 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 the surveyed men who have sex with men engage in anal sex. The 1994 Laumann study suggests that 80% of gay men practice it and 20% never engage in it at all.
The National Institutes of Health (NIH), with information published in the British Medical Journal (BMJ), states that two thirds of gay men have anal sex. Other sources suggest that roughly three-fourths of gay men have anal sex at one time or another in their lives, with an equal percentage participating as tops and bottoms.A survey in The Advocate in 1994 indicated that 46% of gay men preferred to penetrate their partners, while 43% preferred to be the receptive partner. 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%.
Pain during receptive anal sex is formally known as anodyspareunia. One study found that about 12% of gay men find it too painful to pursue, and concluded that the perception of anal sex as painful is just as likely to be psychologically or emotionally based as it is to be physically based. Another study that examined pain during insertive and receptive anal sex in gay men found that 3% of tops (insertive partners) and 16% of bottoms (receptive partners) reported significant pain. Factors predictive of pain during anal sex include inadequate lubrication, feeling tense or anxious, lack of stimulation, as well as lack of social ease with being gay and being closeted. Research has found that psychological factors can in fact be the primary contributors to the experience of pain during anal intercourse and that adequate communication between sexual partners can prevent it, countering the notion that pain is always inevitable during anal sex.
Female to female
While author Tom Boellstorff, when particularly examining anal sex among gay and lesbian individuals in Indonesia, stated that he has not heard of oral-anal contact or anal penetration as recognized forms of lesbian sexuality but assume they take place, author Felice Newman cites anal sex as a part of lesbian sexual practices in her book The Whole Lesbian Sex Book. Daniel Villarreal of Queerty.com suggests that lesbians are better equipped to “teach heterosexual women” about anal sex than gay men are. “Firstly, they’re women and anal sex feels different for women. Women lack that Giggity-spot called the prostate, so anal-loving [lesbians] know much more how anal sex feels as a woman than gay men ever could”, he stated. “Most importantly though, women respond better to women. Ladies can approach the issue by discussing trust, communication, sobriety, HPV-prevention, and knowing your own body.”
Anal sex can expose 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 fragility. Increased experimentation with anal sex by people without sound knowledge about risks and what safety measures do and don’t work may be linked to an increase in sexually transmitted infections. Judy Kuriansky, a Columbia University professor and author, stated, “It really is shocking how many myths young people have about anal sex. They don’t think you can get a disease from it because you’re not having [vaginal] intercourse.”
Unprotected anal sex, colloquially known as “barebacking“, carries an elevated risk of passing on sexually transmitted diseases because the anal sphincter is delicate, easily-torn tissue; a tear can provide an entry for pathogens. The high concentration of white blood cells around the rectum, together with the risk of tearing and the rectum’s function to absorb fluid, places those who engage in unprotected anal sex at high risk of sexually transmitted infection. Use of condoms, ample lubrication to reduce the risk of tearing, and other safer sex practices reduce the risk. However, a condom can break or come off during anal sex, so both sex partners must remain watchful during sex and there is still some risk if one or both partners carries a sexually-transmissible infection.
Unprotected receptive anal sex is considered the sex act most likely to result in HIV transmission. Other infections that can be transmitted by unprotected anal sex are human papilloma virus (HPV) (which can increase risk of anal cancer and typhoid fever), amoebiasis; chlamydia;cryptosporidiosis; E. coli infections; giardiasis; gonorrhea; hepatitis A; hepatitis B; hepatitis C; herpes simplex; Kaposi’s sarcoma-associated herpesvirus(HHV-8); lymphogranuloma venereum; Mycoplasma hominis; Mycoplasma genitalium; pubic lice; salmonellosis; shigella; syphilis; tuberculosis; andUreaplasma urealyticum.
Anal cancer is relatively rare, accounting for about 1 percent of gastrointestinal malignancies, but as many as 4,000 new cases can be diagnosed within a year in the United States, according to theAmerican Cancer Society. Most cases of anal cancer are related to infection with the human papilloma virus (HPV). Anal sex alone does not cause anal cancer; the risk of anal cancer through anal sex is attributed to HPV infection, which is often contracted through unprotected anal sex. 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 (such as a history of multiple sex partners, fifteen or more, or receptive anal sex) and smoking. If a current smoker, there is a fourfold increase in risk, though independent of other behavioral risk factors, such as sexual activity. Receptive anal sex increases the incidence sevenfold. Among the female control group studied, 21.5 percent had reported practicing anal sex, a significant increase from a previous case-control study by epidemiologist Janet Daling (PhD, member of Fred Hutchinson’s Public Health Sciences Division) and her colleagues, published in 1987, in which 11 percent of female controls had reported ever having anal sex. This and other studies also indicate that gay or bisexual sex among men is on the rise, which may account for the increase in anal cancer. “The sharpest increase was among African American men, whose incidence of anal cancer has more than doubled in the past three decades. Black men also had a lower survival rate from the disease.” The study reported that the five-year survival rate for black men with early stage disease was 62 percent as compared to 79 percent for white men with localized cancer. However, the survey also reported that black men were more likely than white men to report having had intercourse with another male in the last year. Regarding all the increases, whether or not sexual practices have changed, Daling, concluded, “[I]t also could be that people are just more likely to discuss their sexual behavior these days”.
Physical damage to the rectum and anus can manifest as generalized ano-rectal trauma, anal fissures, rectal prolapse, and exacerbating hemorrhoids. Adequate lubrication and preparation reduces the risk of physical trauma, while the risk increases with use of alcohol or other drugs that dull sensitivity.
Loss of bowel control is not a highly likely result of anal sex, but may be caused by repeated injury or the insertion of large objects. Kegel exercises have been recommended to maintain muscle tone by a speaker at the Society for the Scientific Study of Sexuality and the American Association of Sex Educators, who noted he had never personally observed “loosening” in any of his patients.
A 1993 study published in the Journal of the Royal Society of Medicine found that fourteen out of a sample of forty men receiving anal intercourse experienced episodes of frequent anal incontinence. However, 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 criticized the earlier study for its inclusion of flatulence in its definition of incontinence.