A "Thousand Mile Smile" is the smile you get when you are really high. It just happens, and it makes you look so stupid. Everyone around you will make fun of you for it. It will begin to hurt your cheeks after a while, but don't fight it. It's part of the fun.
"Look at that Thousand Mile Smile Joey has got goin' on there!"
A method used by London gangsters to scar up their victims. A cut is made at the edge of both sides of the mouth then the victim is kicked in the groin very hard. As he screams the flesh on both cheeks are ripped apart leaving terrible scaring.
I wish some would give George W Bush a five mile smile.
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?"