The act of being so chronically obsessed with yaoi, that you cease to function cohesively when faced with super-cute pictures of couples or fanficts from your chosen fandom.
When, in a manga, mostly during sex, one of the people or both of them have insanely large hands. We're talking hands that are larger than their heads.
When images of yaoi are sent around to random people at anime conventions using a Bluetooth connection, using (nearly always) a mobile phone. It was created by a UK cosplayer called Cassie.
Convention-goer #1 'Wait, who just sent me a picture of Naruto and Sasuke making out?!'
Convention-goer #2 'Dude...someone must be yaoitoothing you'
1. A girl who is obsessed with yaoi to a dangerous amount.
Be wary about allowing her near two attractive guys, because she may force them to make out. Some popular pairings are SasuNaru, Ed/Al, Yuki/Shuichi, and Raito/L. It may be hard to discern who is a yaoi fangirl and who isn't, and remember: never assume they don't love yaoi just because they are 13 or under.
The author of this definition is an insane, rabid yaoi fangirl.
A very shy and cute girl everyone loves. She's vulnerable to teasing and while she may act innocent she's actually a huge closet pervert. They usually have a lot of friends and are cared and loved for by everyone for always bringing joy and fun to your lives.