Blueshell's advice is spot on, dont give her your number. From Blueshells advice you should have a sleeve set aside for her, set it up before your shift. I like the idea of telling her something about her she doesn't know.
Maybe try "When you finish your tasty beverage write you favorite color here ______ and return it _______ (you tell her where, to the counter or in the tip jar, or at the table, whatever works)" Then the next day tell her what that means on a new sleeve.
http://www.care2.com/greenliving/favori ... ality.html#
You could go with the esp trick. On the sleeve "Pick a number between 1 and 10 and write it here ___. Now look on the inside of this sleeve." On the inside you write, "You choose 7 I can read you like a book" or "7 you and everyone else" or just "7" be creative. She will be stunned if your right, but should be funny if your wrong.
Or you could do a joke. On the outside something like "How did the farmer find the sheep in the tall grass? other side for answer" then on the inside the punchline "Pleasurable". Maybe something less sexual, but I don't know any jokes like that.
CHAT
