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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!"
by A Sea Shell October 09, 2011