I use this at parties/bars sometimes and have had pretty good success with it. Anyways this is best used when you've been dancing with a girl for a bit (not sure how this would work on a girl you met 5 minutes ago).

I'm sure many of you have been in the scenario where you are dancing with a girl for a while and it starts to get old (just typical grinding you'd see at most clubs or parties). Obviously there are other methods to add more excitement to dancing, but this is just one I use sometimes.

Anyways so after a bit of dancing. I'll playfully tell the girl (usually in her ear while she's grinding):

"You're a pretty good dancer"...pause (critical as she probably feels good about herself now and thinks she's an awesome dancer).... "I'd give you a 5.5/10" playful smile ...pause "6/10 at best"

Then usually at this point she gives the "omg you did not just say that" look while I have a shit eating grin on my face. At which point she then tries to prove herself and escalates the dancing.

Warning: Use at your own risk. A chaffed dick is a common side effect.

Pro-tip: If you use some variation of this line with her around her friend and then hint that her friend is the better dancer, you now have two girls trying out for pole position.