Really like this opener, and figured it's worth having a follow-up in the unlikely event one of the girls (in a drunken/emotional state) actually feels like slapping someone and happens to let you have it. Because this wouldn't look good to other girls in the room who see this and could ruin the rest of your game in that location.
What I'd suggest is, after being slapped, you laugh and shout "Thank you!" and grab her for a hug, followed by "The real bet was that I wouldn't be able to get a 'nice girl' to slap me in public.. you've just won me £10/$10!!".. then continue with your routine.
Doing this will:
- Make the girls laugh.
- Make other girls watching around the room think that you know each other and it was just a playful slap.
- Allow you to hug her (which can also be followed with the usual push back "ok that's all you get").
What do you think?