Overview
In human sexuality, a threesome is commonly understood as "a sexual interaction between three people whereby at least one engages in physical sexual behaviour with both the other individuals". Though threesome most commonly refers to sexual activity involving three participants, it is also sometimes used to apply to a long-term domestic relationship, such as polyamory or a ménage à trois.
A threesome is a form of group sex which may occur in private situations, such as spontaneous sexual activity among three friends or in the context of casual sex or a hook up. Alternatively, it may take place in specific contexts or environments which allow for sex, such as swingers events, orgies or sex parties.
Threesomes are a common element of sexual fantasy, and are commonly depicted in pornography.
Types
The people in a threesome may be of any gender and sexual orientation. Each participant may engage in any type of sex act with one or both of the others, such as vaginal, anal, oral, or manual sex. One or more of the participants may engage in autoerotic sexual activity, such as masturbation, possibly without physical contact with the other participants. It is a matter of subjective definition whether participation of a third person without physical contact constitutes a threesome and this sort of sexual activity might instead be interpreted as voyeurism or cuckolding or cuckqueaning. Troilism is a term that encompasses both threesomes and cuckoldry, although its usage across literature is inconsistent.
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