Frotteurism
In the context of human sexual behavior, frottage or frotteurism is the act of obtaining sexual gratification by rubbing one's (clothed or naked) body against another person. Frotteurism carries a connotation of "anonymous and discreet rubbing" in a public place—like on a crowded train. The contact may be mutual or a one-way exchange. A person who practises frotteurism is known as a frotteur. As with most other sexual practices, frottage with a non-consenting person is regarded as a form of sexual assault in most jurisdictions.Frot (short for frottage) or "phrot" (alternate spelling) among homosexual men tends to imply penis to penis rubbing in a conventional private context. Advocates of this practice represent it as a safer and more erotic alternative to anal sex. The female equivalent is sometimes referred to as tribadism.
Two people engaging in clothed frottage in a manner that simulates intercourse is known in the vernacular as "dry humping". A modern dancing style which involves partners rubbing their clothed bodies on one another is called grinding.
see also: outercourse, interfemoral intercourse