A female that will makeout, tease, allow hands on the breasts and crotch, grinding, fondling, and touching, but no penetration. Typically this category of female doesn't consider giving head to actually be sex.
Jim: I went out with Karen last night
Friend: Did you score?
Jim: No, I've got blue balls. She's such a makeout slut.
A girl that will make-out with any guy that she finds somewhat interesting, but refuse to go much farther than that and/or start a relationship with that guy.
Many Make-out sluts are out to make out with as many guys as they can in a certain period of time.
Advanced make-out sluts will often keep a list of all the guys she has made-out with and sometimes will even give them grades, whether it be a A-F scale or 1-10 scale.
Joe: So how'd it go with u and Amy last night?
Rob: Last night was pretty fun, but she's just a make-out slut so I don't think i'll b talking to her anymore. She got what she was trying to get. She's already working on trying to make-out with Drew tonight.
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?"