A.T.M. Share definition Flag A.T.M. means Ass To Mouth. As in, your banging a chick in the ass, you pull it out and she gives you head. Yo, that chick I took home from the bar last night, we did A.T.M. A.T.M. by ItIsI November 9, 2012 0 0 Get merch Get the A.T.M. mug. Buy Now — $32.95 See more merch