Nerd: " Watch me do a triple backflip while rotating at 2.4 m/s at 57 degrees south of west, and land in the water creating a splash radious of exactly 3.4256 meters...."
Guys: " Uh.... nvm this guy is nerding it up, peace "
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?"