The word can be used in a sexual or an "imma say some random shit to piss the class off" type of word.
You use your friends or classmates name before you say "It's So BIG!!" Remember to say It's So Big in a very high pitched voice.(Make sure your classmates or friends are chill)
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.
FRIEND A: "Did you just take a stealthie of me?"
FRIEND B (turning phone around): "no I was just using snapchat's new filter, see?"