Whip Catch

Throw the diabolo up.

Put both hand-sticks in one hand in a V shape.

Turn side on to the diabolo and bring your hand down creating a loop in the string which shall catch the diabolo.

This trick is really impressive but does take a little while to get.

A Tip to make it easier

Practice holding the diabolo in your non-dominant hand and whipping with your dominant and aiming one of the sticks at the axle. When whipping with my right hand I make sure to aim my left stick at the axle and vice versa.