Turn the hand with the sleeve partially covering it so that your palm faces upwards. This is the hand that will hold the coin.
With your dominant hand, place the coin on your upturned hand. The coin should lie in the center of your palm.
First, snap your hand above the coin a few times, close to the coin but never touching it. On your last snap, make your snapping finger hit the
coin so that it flies into your sleeve.
You'll need to practice this trick a few times by yourself to make sure you can reliably flick the coin into your sleeve.
Hold both of your hands with palms facing upward to show the audience how the coin can't be seen. Then turn both hands downwards. You can do this a
few times and make a show of it, and the coin will rest in your sleeve as long as you don't tilt your arms too far downward.