A Saint Paul Handshake is a drink you order at a bar. It consists of a shot of Jameson Irish Whiskey paired with a pint of Hamms beer. Hamms was established in Saint Paul, MN and became the fifth largest brewery at one point. Saint Paul is also a very Irish city. Hence the Jameson.
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?"