The easiest way to do the trick was to take both handles in your left hand and grab the bottom lines with your right hand. Pull both bottom lines sharply and then release. The flaps of the Rev get should get pulled towards you and then released quickly enough so that they spin right back and over the leading edge. The kite should now be wrapped around its lines. Pull sharply on both handles (in your left hand) to unwrap it. Then pull the bottom lines again to wrap, pull to unwrap, etc., etc....
Get the timing right and you get the characteristic "Flic-Flac" motion as the kite wrap, unwraps, wraps, unwraps, etc. Looks pretty cool.
A slightly different method - hold one handle in each and and jab your hands down sharply (to pull mainly on the bottom lines) and then release. It seems to require more precision and control, but had the benefit of not slicing his fingers up on the lines :-)