Indian War Drum
A sex act whereby two women lay on their backs with their butts resting on a third man/woman's lap, who must be sitting indian style. The sitter then proceeds to go to town on the two women with dildos in alternating thrusts creating a war drum like sound.
Jeff: Could you get a stiffy watching Pat do the Indian War Drum to Sarah and Bizzy?
Ben: I have one just thinking about it.
Ben: I have one just thinking about it.