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. Three categories of intercourse are commonly practiced: vaginal intercourse, involving vaginal penetration anal penetration and oral sex, involving mouth-on-genital stimulation. Though sexual intercourse generally involves the penetration of the body of one person by another, or direct stimulation of the sex organ of one by another, a sex position may not necessarily involve penetration or direct stimulation, and may be non-penetrative. Sexual acts are generally described by the positions the participants adopt in order to perform those acts.

Sex positions are positions that people may adopt during or for the purpose of sexual intercourse or other sexual activities.