When you need to abruptly end a conversation and have simply had enough contact with other humans. It can be used to end a conversation at any point, and is especially useful if the person is repeating themselves.
John: so yeah Sandra was like totally into me and I was..
Me: ok thanks bye (OTB) (hangs up, gets up and leaves)
John:….totally into her.. hey Steve are you there / where are you going
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?"