A warning, or threatening request, spoken by a person in order to prevent another person trespassing on their 'territory' or 'hood'
stranger: "who's gotbud round here?"
"local": "oi cunt, quit bustin' ya hole round these ways"
stranger: "you did NOT just say that cunt, imma get you"
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?"