As in defecating in a jacuzzi.

To rain on one's parade resulting in a "what the hell?" expression. Also, a non-negotiable part of an event or circumstance that ruins the rest of the event or circumstance. Term sometimes interchangeable with party foul.
You're really going to make me work Thanksgiving? That's poo in the 'cuzzi, man!

T: Oh, by the way... I accidentally let Ugly Matt buy our drinks, so he's probably going to come over here and talk to us.
N: ...Poo in the 'cuzzi, dude! POO IN THE 'CUZZI.
by Norma R November 23, 2006
Get the poo in the 'cuzzi mug.