The term tribadism derives from the Greek word τριβάς ( tribas), which in turn comes from the verb τρίβω ( tribō), 'rub'. It may also involve vaginal penetration by use of the fingers, a dildo or double penetration dildo. In modern times, the term typically refers to various forms of non-penetrative sex (or frottage) between women. Women accused of having been penetrative during sexual activity were subject to ridicule or punishment. The term tribadism originally encompassed societal beliefs about women's capability of being penetrative sexual partners. A variety of sex positions are practiced, including the missionary position. This may involve vulva-to-vulva contact or rubbing the vulva against the partner's thigh, stomach, buttocks, arm, or other body part (excluding the mouth). Tribadism ( / ˈ t r ɪ b ə d ɪ z əm/ TRIB-ə-diz-əm) or tribbing, commonly known by its scissoring position, is a lesbian sexual practice in which a woman rubs her vulva against her partner's body for sexual stimulation, especially for stimulation of the clitoris. Two women engaged in the missionary position of tribadism and rubbing vulvas, one of the various positions in which a woman rubs her vulva against her partner's body for the purpose of sexual pleasure.