Group sex is sexual behavior involving more than two participants. Participants in group sex can be of any sexual orientation or gender. Any form of sexual activity can be adopted to involve more than two participants, but some forms have their own names. Group sex most commonly takes place in a private sex party or semi-public swinger gathering, but may also take place at massage parlors or brothels or, in some jurisdictions, at purpose-built locations such as sex clubs. In places where non-monogamous sex is taboo or illegal, group sex may take place in private or clandestine locations including homes, hotel rooms, or private clubs. Fantasies of group sex are extremely common among both men and women. Many forms of sexual behavior were reported by Kinsey's subjects, but the official Kinsey Reports website does not mention threesomes or group sex in the summary of Kinsey's findings. Group sex is a subgenre in pornographic films. Terms In principle, any sexual behavior performed by more than two people can be referred to as group sex, but various terms are used to describe particular acts or combinations of people. Many swingers argue that non-swingers have conflated the terms because of lack of understanding and that there are distinct differences among the terms with specific meanings as to number, intent, sexual orientation, and familiarity of the persons involved. Circle jerk: Group masturbation among men, usually sitting in somewhat of a circle formation. Daisy chain: Group of participants perform cunnilingus or fellatio on each other in a circular formation, permitting each participant to both give and receive oral sex simultaneously. Gang bang: A number of people performing sex acts on one person, either in turn or at the same time. Threesome or three-way: Three people all having sexual relations, not necessarily simultaneously. Not to be confused with ménage à trois (literally, "household of three"). Foursome or four-way: Sex between four people. Not to be confused with ménage à quatre (literally, "household of four"). Double penetration: When a person is entered or penetrated in the vagina and/or anus by two people at the same time. This is usually when one person enters the anus while another enters the vagina; however, it also refers to two simultaneous penetrations in the same orifice. Spintrian: A term used by Suetonius to describe sexual group practices indulged in by the emperor Tiberius on Capri. Monogamous group sex or same room