When playing tag, or another game where there is a 'base' or other type of safe zone, the person 'it' stands outside the zone, waiting for the person to leave so as to tag them.
person1: *runs into base*
person2: *stands outside base waiting for them to try to escape*
person1: Hey! No puppy-dog gaurding!
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?"