The brown (and sometimes other colors such as green, black, etc.) watery goo that is violently ejected from your anus during those long painful sessions of explosive diarrhea. Known causes: beer (in large enough quantities), Mexican food (in any quantity), stomach viruses (contracted from dirty bathrooms, Mexican food places, etc.), and from having sex with ugly women (or so I've heard).
Mary was mad at Joe because he stole her stapler. She confronted him and said "hey, Joe, why don't you go suck down a turd slurry."