This is commonly due to prohibitions against anal sex among males or teachings about the procreative purpose of sexual activity.
By contrast, people also regard anal sex as a natural and valid form of sexual activity that may be as fulfilling as other desired sexual expressions.
By contrast, each person's sphincter muscles react to penetration differently, the anal sphincters have tissues that are more prone to tearing, and the anus and rectum do not provide lubrication for sexual penetration like the vagina does.
Researchers say adequate application of a personal lubricant, relaxation, and communication between sexual partners are crucial to avoid pain or damage to the anus or rectum.
The vaginal walls contain significantly fewer nerve endings than the clitoris and anus, and therefore intense sexual pleasure, including orgasm, from vaginal sexual stimulation is less likely to occur than from direct clitoral stimulation in the majority of women.
Indirect stimulation of the clitoris through anal penetration may also be caused by the shared sensory nerves, especially the pudendal nerve, which gives off the inferior anal nerves and divides into two terminal branches: the perineal nerve and the dorsal nerve of the clitoris.
Stimulation from anal sex can additionally be affected by popular perception or portrayals of the activity, such as erotica or pornography.
In pornography, anal sex is commonly portrayed as a desirable, painless routine that does not require personal lubricant; this can result in couples performing anal sex without care, and men and women believing that it is unusual for women, as receptive partners, to find discomfort or pain instead of pleasure from the activity.
Besides the shared anatomy of the aforementioned sensory nerves, orgasm by indirect stimulation of the clitoris or G-spot area through anal penetration may be aided by the close proximity between the vaginal cavity and the rectal cavity.The review suggests that anal sex is exotic among the sexual practices of some heterosexuals and that "for a certain number of heterosexuals, anal intercourse is pleasurable, exciting, and perhaps considered more intimate than vaginal sex".The likelihood of pregnancy occurring during anal sex is greatly reduced, as anal sex alone cannot lead to pregnancy unless sperm is somehow transported to the vaginal opening.While some women find being a receptive partner during anal intercourse painful or uncomfortable, or only engage in the act to please a male sexual partner, other women find the activity pleasurable or prefer it to vaginal intercourse.In a 2010 clinical review article of heterosexual anal sex, the term anal intercourse is used to refer specifically to penile-anal penetration, and anal sex is used to refer to any form of anal sexual activity.