Tribadism

Tribadism (trib'ad-izm) [G. tribein, to rub, + -ismos, condition] is a sexual practice where two women rub their external genitalia against one another for clitoral stimulation. An alternative name for this practice is frottage. The word is derived from the obsolete word tribade, meaning "lesbian", and until the middle of the 20th century (sometime before 1965) meant "lesbianism". Also known in the vernacular as donut bumping, monkey bumpin' or bumping uglies.