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. Frottage 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 practices 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.