A term used in the form of "emotionally" connecting with somebody new.
Derived from the construction toy/puzzle known as "k'nex" where in which pieces of plastic are connected together to make buildings, cars etc...
For example,
Two guys are in a bar, one guy goes over to a girl and they talk for half an hour, gaining her phone number. The other guy then nudges him and says
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?"