One who walks using the cheeks of their buttocks. Asswalking first performed on the short-lived cartoon network series "Cow and Chicken" by a character known only as "the red guy". May also mean a person who is not disabled but has a ridiculous walk which makes them look like an asshole.
Similar to the idiom, "Wear Your Heart On Your Sleeve" but instead of expressing your emotions freely, you (or someone else) show how much of an asshole you are.
Cal: Yeah, so I punched him in the face for taking the last slice of pizza.
Rudi: It was his birthday, assjacket.