look up any word, like bae:
 
2.
STYFYB is an acronym that was invented by a bored Facebook user to shorten the phrase " She's Too Young For You Bro!"
If she watches the movie the whole time, STYFYB
If she is amused by Nyan Cat, STYFYB
If she thinks 1337 is a year, STYFYN
by unknownVS13 August 20, 2011
 
1.
short for "she's too young for you bro," the expression popularized by the TV show Jersey Shore, Jerry LaVigne Jr. and the facebook group "If she ______ she's too young for you bro" that collected hundreds of thousands of likes and tens of thousands of wallposts within only a few days.
"if you have to pretend your penis is a train or a plane to get it in her mouth styfyb"

"if she's looking up this definition, then styfyb!"
by br0lias August 17, 2011