forcing a woman who is riding you, to take a dump in your belly button and stomp it with her ass cheek until it forms a pancake
i made laura give me a mud pancake, it was amazing!
When you are having anal sex with a girl and you pull out and put it into her vagina.
Friend #1: I was have amazing anal sex with that filthy little filly Stacy and I pulled it out and put it deep in her bum, straight mud-flappin' bro.
Friend #2: Amazing, pure class.
When your having sex doggystyle and the girl explosive diarrheas on the man's testicles.
"Did you hear what happened to Josh? Melissa gave him a West Virginia Mud Flap"
The act of inserting a clear plastic tube in the anus, and inserting the other end of the tube in the anus of a "trusted" partner and shitting back and forth into each others asshole.
Earl and Jim-Bob got drunk and built a Texas Mud Bridge the other night.