becon your intended target towards you with your finger in the standard and well practised manner. When she or he approaches, say the following;
If I can make you come with one finger, just think what i could do with the rest of my body.
Try hopeful smile and get ready to duck.
(This one, as moronic as it sounds, actually worked for me once. well it started a conversation at least, the rest was probably due to my irresistable personality or her ability to drink me under the table)