When you are up so late or get so little sleep that you have the same symptoms as if you had been out at a bar/party pounding down the drinks... headache, stomachache, hungry, everything is loud, etc.
Man, I was at that partylast night and didn't have a drink ... but was out so late I'm sleep hungover!
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?"