The act of ruining someones good mood by introducing bad news or behaving like a douche-bag.
D-Bag: "This steak sucks. Why are we eating here? I think McDs has better food."

Dude: "Shut the F*** up! It's my F*** Birthday! Seriously you are shitting in my Cheerios!"
by Burgerpickle September 2, 2010
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(true story) when you are about 8 years old and enjoying a bowl of some honey nut cheerios in front of the TV and your older brother casually walks up to you half turns lifts his leg and farts your direction and a little diarhea accidently falls into your bowl of cheerios.
OH MY GOD!!! MOM! Sam just took a shit in my cheerios!
by -Blackbiurd August 29, 2017
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