Mr. Marcin,
I suggest urination. People don't like pee, especially when it's someone else's stream coming in direct contact with them. And if they are into it, well they're into just about everything, and that is what we call a keeper. Take her home and do all the things you never dreamed any one would do. Then never let go of that person as you have found your sole mate. And live happily ever after and all that.
~Dr. Willie
P.S. if you don't want to pee on somebody for fear of being arrested or just a shy bladder, try telling them to fuck off.