In a sexual context, “ATM” is an acronym that stands for “Ass to Mouth.” This term refers to a sexual act in which a person penetrates another person anally with their penis, sex toy, or other object, and then the penetrated person performs oral sex on the penetrator without cleaning or washing the object in between. This practice can increase the risk of transmitting sexually transmitted infections and should be avoided or practiced with caution and communication between partners.