I think I just came across gold. The other day I was in a bar with a girl that I have a big crush on and we were in a playful mood talking and drinking and I started playing with her like this:

Me: Can I ask you a personal question? She: Yeah, what? Me: Under your clothes are you a boy or a girl? She: lol, lol, girl of course... bla bla... Me: well, I don't know, you can never be sure in this city. I don't like any surprises. She: I have boobs, look :) Me: Well, that is the easiest thing to fake. Let me see your neck, let's see if you have Adams apple. She stretches her neck, and I examine her neck running up and down my finger. Me: Ok, no Adams apple. But maybe you had that removed, let me see your feet, you know, men have big feet. She shows me her feet. I hold her foot looking at it with a great concern. Me: Hmmmm, pretty small but that still doesn't mean anything. You know men have hair on top of their fingers, let me see. I take her hand and examine her fingers. No hair, that's a good sign! So I guess you are a girl, but we'll see, I don't like any surprises!

She absolutely loved my teasing, laughing and trying to prove me that she was a girl.

Just wanted to share this with you guys to try that on girls in the field and report back here so we can see if that works in general or if it was just a fluke.