Sexual penetration is a sexual activity that involves the entry into a bodily orifice, such as the vagina, anus or mouth, with a body part or an object.
When a penis penetrates a woman's vagina, it is called vaginal or sexual intercourse; when a penis penetrates another's anus, it is called anal intercourse. Penetration of the mouth by a penis is called fellatio. Penetration of the vagina by the tongue of another is one of several forms of cunnilingus. If one or more fingers are used to penetrate an orifice, it is called digital penetration. Penetration of an orifice with an object, such as a dildo, vibrator or other sex toy may also be referred to as sexual penetration, but not usually referred to as sexual intercourse. The use of a tongue for penetration is a form of oral sex, although oral sex may also occur without either the tongue entering any orifice, or any object entering the mouth.
Acts involving sexual penetration are often portrayed pornographic films. This may include double penetration, where one person is simultaneously penetrated in multiple orifices, by two partners.
Many sex crimes include specified forms of sexual penetration of the victim as part of the offense, with such penetration resulting in more serious consequences than nonpenetrative activities. For example, under the laws of the U.S. state of Oregon, "Unlawful sexual penetration in the first degree" is a felony that occurs where the offender "penetrates the vagina, anus or penis of another with any object other than the penis or mouth of the actor", if the victim is "subjected to forcible compulsion", or is "under 12 years of age", or "is incapable of consent by reason of mental defect, mental incapacitation or physical helplessness".[1]
Furthermore, at various points in history, different kinds of penetration have been considered obscene, resulting in prohibitions against pornographic materials containing them.