Tribadism 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. This may involve vulva-to-vulva contact or rubbing the vulva against the partner's thigh, stomach, buttocks, arm, or other body part. A variety of sex positions are practiced, including the missionary position.