me: hey, wanna slap my face?
girl: why?
me: well I am well behaved and always treat women good so I never got a slap on my face. Just wondered how it feels
girl: oh so you are really that nice of a guy? Oh so you a sweatie? Oh then you did not deserve that! (or whatever are the answers)
me: just respond to what she says - continue conversation.
Of course if you don't want to be seen as a "good boy" you show that in your later convo - cocky/funny/friendy neg etc etc. You can do it that much that she says "well you are not that nice after all" - but in a good way. Positive vibe


pretty good at bars. But on the second hand - any opener is good at bars

im almost certain they'll just be freaked out by it. if ur lucky she could be the social type and talk to u, but its pretty random and akward to say "hey wanna slap my face"

Actually they don't too often. If they don't like you they may, but if they like you they play with you and it usually ends into more of a kino: after they give me a friendly slap I switch topic to the thing that now I should slap her back since it would be fair (or any other reason you think of), but I say since I don't hit girls I should slap you somewhere else and it ends up me giving her friendly booty slap.
Sorry for my English, but you should see what I mean. Everything goes in a very playful way with a lot of both way smiles. If you project "serious" style this may not be for you. It depends what you say but after she gave me a slap it takes me 2-4 sentences with her till I get that booty slap.
But again this is more of a bar/club game and not day game. At day game yeah you must be a master not to freak them out.

By the way if you are from US you might see it in a bit different way since I am in Europe and we are a little bit more used into touching people you just met, especially during night game. Maybe thats why I don't really understand where are you comming from with her being freaked out comment