piss in (one's) cereal(redirected from piss in their cereal)
piss in (one's) cereal
rude slang To upset, irritate, or disappoint one, especially to an extreme or excessive degree. Sorry to piss in your cereal, but you won't get any credits for the class unless you attend every single lecture. A: "Watch out, the boss is in a foul mood today." B: "Wow, I wonder who pissed in his cereal?"
See also: piss
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.