Sexual intercourse

Sex, more formally known as sexual intercourse, coitus, or copulation, is an intimate social activity typically involving the insertion of the erect male penis inside the female vagina and followed by thrusting motions for erotic pleasure, biological reproduction, or both. This specific type of sex is also known as vaginal intercourse (or vaginal sex). However, other forms of penetrative sexual intercourse also exist, including anal sex (penetration of the anus by the penis), oral sex (penetration of the mouth by the penis or oral contact with or penetration of the female genitalia), fingering (sexual penetration by the fingers) and penetration by use of a dildo (especially a strap-on dildo), and vibrators. The desire for these activities is grounded in natural human instinct and they involve physical intimacy between two or more people, usually enacted by humans solely for physical-emotional pleasure, sometimes contributing to human bonding. There are different views on what constitutes sexual intercourse or other sexual activity, which can impact views of sexual health. Although sexual intercourse, particularly the term coitus, generally denotes penile–vaginal penetration and the possibility of creating offspring, it also commonly denotes penetrative oral sex and penile–anal sex, especially the latter. It usually encompasses any sexual penetration (a term especially common in statutory law), while non-penetrative sex has been labeled outercourse, but non-penetrative sex may also be considered sexual intercourse by some people or in some less-common definitions. Because people can be at risk of contracting sexually transmitted infections during these activities, safer sex practices are recommended by health professionals to reduce transmission risk. Various jurisdictions place restrictions on certain sexual acts, such as adultery, incest, sexual activity with minors, prostitution, rape, zoophilia, sodomy, premarital sex and extramarital sex. Religious beliefs also play a role in personal decisions about sexual intercourse or other sexual activity, such as decisions about virginity, or legal and public policy matters. Religious views on sexuality vary significantly between different religions and sects of the same religion, though there are common themes, such as prohibition of adultery. Reproductive sexual intercourse between non-human animals is more often called copulation, and sperm may be introduced into the female's reproductive tract in non-vaginal ways among the animals, such as by cloacal copulation. For most non-human mammals, mating and copulation occur at the point of estrus (the most fertile period of time in the female's reproductive cycle), which increases the chances of successful impregnation. However, bonobos, dolphins and chimpanzees are known to engage in sexual intercourse regardless of whether the female is in estrus, and to engage in sex acts with same-sex partners. Like humans engaging in sexual activity primarily for pleasure, this behavior in these animals is also presumed to be for pleasure, and a contributing factor to strengthening their social bonds.