I don’t have to remind Smooth Nation that no matter what we learn here about confidence and subtle touch-testing to determine degree of interest, we’re talking about very light and brief playful taps on the shoulder or maybe wrist, to done when one observes laughter and a relaxed manner on the part of the woman. It’s very incidental, and timed to accompany a witty statement, or your own laughter at hers.
What it is not, is this:
Only guys with no self respect, violate strangers in public. That’s about a power trip, PullJoy© is about standing out from the crowd, with charisma and high social value. Be engaging, be a listener, and if the signals are there (she doesn’t want to end the conversation, she giggles even at marginal attempts at humor, she gently pokes you after a comment you make, she’s got the whole swinging leg thing going while she’s seated), pat the back of her hand to coincide with a good-natured jest.