A sex position is a position of the body that people use for sexual intercourse or other sexual activities. Sexual acts are generally described by the positions the participants adopt in order to perform those acts. Though sexual intercourse generally involves penetration of the body of one person by another, sex positions commonly involve penetrative or non-penetrative sexual activities.

Three categories of sexual intercourse are commonly practiced: vaginal intercourse (involving vaginal penetration), anal penetration, and oral sex (especially mouth-on-genital stimulation).[1] Sex acts may also involve other forms of genital stimulation, such as solo or mutual masturbation, which may involve rubbing or penetration by the use of fingers or hands or by a device (sex toy), such as a dildo or vibrator. The act may also involve anilingus. There are numerous sex positions that participants may adopt in any of these types of sexual intercourse or acts; some authors have argued that the number of sex positions is essentially limitless.