1 definition by TheRipper19496
When there isn't any toilet paper in the restroom you've just pooped in, and you have to make a dash with poop on your asshole to another one.
Corissa: Why are you out of breath, and, by Jove, what is that smell?!
Kevin: Sorry babe, I'm on a Mud Run.
Kevin: Sorry babe, I'm on a Mud Run.
by TheRipper19496 June 19, 2015