Similar to motorboating, but done between someone's ass cheeks. When someone places their mouth between someone's ass cheeks and then shakes their head violently while making motor sounds with their lips.
As coined in Episode 86 of the Wheels Off Liberty podcast by one Jamie Crane.
I've been mudbugging so much that I can't evensmell shit anymore!
When you put a fat dip in, sit in your rocking chair on the front porch, and have your sister or cousin lay on their stomach and spread her butthole. Then you proceed to spit your dip in to her butthole. She then makes a Ding! sound effect mimicking a metal mudjug.
Hey man you want a dip?
Hell yah! Tell your sister to come out here, we need the ol Mississippi mudjug.