I've used this many times to open strangers at a bar where free peanuts are served, or if I'm offering a piece of gum or a breath mint. Instead of describing it I'll just link to a clip of the Jackie Chan movie where I learned the trick years ago -- it's the second one.

You put the peanut/mint in the crease of your middle and ring finger, and slap the palm of your hand to pop it into your mouth. It took me a few hours of practice and I still miss about 25% of the time, but it usually gets a girl or a group of people laughing and engaged. Challenge a girl to try it and mix in a little teasing if they miss and light kino/high fives if they do it successfully. If it's after a dinner date I might bust this out with mints, and make a joke about our newly fresh breath before going in for a kiss.