Tribadism is a common non-penetrative sexual act between women.[11][12][19][20] It is often known by its "scissoring" position, and is also referred to as frottage or in popular slang as dry humping. It involves a woman rubbing her vulva against her partner's vulva, thigh, stomach, buttocks, arm, or another body part. This may be achieved in a number of sex positions, including a missionary, a woman on top, doggy style, scissoring or other position.[21][22] It may be accompanied by fingering or penetration with a dildo.[11][20][23]