An individual that bites ones butt-cheeks. Usually resulting in a case of swollen colon, staff infection, or a bite mark. Usually the butt-cheek is firm and very smooth allowing the ass muncher(s) to get the most accurate nibble or sometimes bite. people who get assmunched...usually go into a state of horniness where they start to develop long boners and occasional discharges of the vaginal canal.
Lindsay is the dumbest ass muncher. She bit Mr.Decker's wrong buttcheek. This turned Mr.Decker off which resulted in him whacking her in the face with his ballsack(s).