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Having Sex from WikiPedia:

Sexual intercourse, also known as copulation or coitus, commonly refers to the act in which the male reproductive organ enters the female reproductive tract. The two entities may be of opposite sexes or not, or they may be hermaphroditic, as is the case with snails. In recent years, penetration of non-sexual organs (oral intercourse, anal intercourse) or by non-sexual organs (fingering, fisting) are also sometimes included in this definition. Traditionally, intercourse has been viewed as the natural endpoint of all sexual contact between a man and a woman.

Non-penetrative sex (oral sex may or may not be penetrative) and mutual masturbation have been referred to as "outercourse". "Outercourse" is something of a misnomer, as it contrasts "outer" with "inter" but the "inter" in "intercourse" means "between two people" or beings. It does not describe being inside or outside of the body. The word sex, in the context of sexual intimacy, is often, if not universally, understood to include any mutual genital stimulation, i.e. both intercourse and outercourse.

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