Best definition
You’re only in college once. A reason to do anything and everything in college because you only get 4 years.

“Dude never turn down a rim job from a sorority girl, YOICO!”

“You have to get roofied sometime, it’s college, YOICO!”

YOICO: define #2
You’re Only In College Once.
I am going out tonight even though I have a test tomorrow, YOICO.