Not quite a double date, but not exactly a date either. It's when you invite someone out on a date, and they pull a defensive maneuver and bring a friend along, as a date shield.
Dude, I asked out that hot chick Sally on a date Saturday to coolparty. She said yes, because she knew it was a cool scene, but she turned it into a one-and-a-half date, bringing along her BFF Tina to cock block.
A twosome would involve two normal-sized people, so therefore a one-and-a-halfsome would involve a normal-sized person and a person half the size of a normal person, or a midget.
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?"