a container filled with excrement--used as a practical joke or revenge tactic.

Place a poop cup in a well concealed spot to ensure longevity and sustained satisfaction.

Farting into your cupped hand and then quickly swinging your hand around to a friend's nose like a ladle, carrying with the true essence and concentrated stink of your nasty fart. Share your strong fart with one friend instead of allowing it to weakly dissipate in the room.

A cup full of poop which is hidden in a victim's dwelling or vehicle to inflict revenge and instill fear in the heart of said victim.

it's poop... in a cup, duh
used to show extreme stench or suck-ass ness

Profanity that is appropriate for only the worst situations in life.