Anal sex or anal intercourse is generally the insertion and thrusting of the erect penis into a person's anus , or anus and rectum , for sexual pleasure. While anal sex is commonly associated with male homosexuality , research shows that not all gay men engage in anal sex and that it is not uncommon in heterosexual relationships. As with most forms of sexual activity, anal sex participants risk contracting sexually transmitted infections STIs. 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 lubrication like the vagina does , so they can easily tear and permit disease transmission, especially if a personal lubricant is not used. Strong views are often expressed about anal sex.
Greek sex is a euphemism for anal sex. Ancient Greeks were accepting of romantic or sexual relationships between males. However, anal sex was not a universally accepted practice outside of Greece, and was therefore the target of jokes in Roman comedies and plays. Romans often used Greek settings and characters as the backdrop for explicit acts of anal intercourse, indicating that the Romans may have considered anal sex to be specific to Greek culture. Ancient Greek language had no words for "homosexual" and "heterosexual.