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.
At a party, you enter in a conversation with a friend and either a monet or other cool-from-afar type of person, usually long-winded, a close talker, or other party foul-esque character . When your friend makes a hasty retreat, leaving you alone with the third party to talk your ear off, he or she has been handed off.
N: You totally pulled a hand off with that asshole back there, you dick!
L: Sorry dude, he wouldn't stop talking about his new rice cooker; I thought you'd be better suited to deal with it!