when a person wipes his rectum onto the outer region of a coffee mug(usually where the mouth will be placed) with the objective to trick another person in using that mug unknowingly
My boss took out all his crap on me today so I ass mugged him to make me feel better.
A phrase idiots use to make themselves seem superior to fans of the harry potter series.
Douchbag - "Hey, muggle ass nigga? Fuck you! (insert immature sex joke here)
Harry Potter fan - "Yes, and you're an immature loser whose social skills are so deplorable that your only means of communication is to make sexual innuendos that only an elementary school student would find funny. All for the sake of generating some kind of positive emotional reaction from the people around you, thus allowing you to cope day by day with you incredibly low self esteem.
Douchbag- (Proceeds to run and cry shouting "My father will hear about this" Draco Malfoy style!