Bucking the mustard 

Bucking the mustard is basically having diarrhea so bad it's squirting yellow from your rectum like someone's squeezing a bottle of mustard and it farts towards the end. Generally followed by the sound of someone scrubbing the shit splatters off the side of the bowl.

Man, I was up all night bucking the mustard.

Jill: Yeah don't bother coming to work, I don't want what you have.

man: I will call tomorrow and let you know if I am feeling better.
Jill: Okay

Bucking the mustard by rhonin66 March 2, 2021