A juggling pattern involving an under-arm throw followed by a downward grab. Can be very flashy if done with broad movements and quick hands. A good practice exercise is to use two balls, throwing continuous under-arm throws and alternating which arm is on top for each throw.
Andy Lewis gives an excellent explanation on www.juggling.org, in the tricks section. To start, have two balls in the right hand, and have your right arm crossed under your left. Then :
1) Right hand throws ball 1 (on left side), vertically.
2) Right hand comes to the right, throws ball 2
3) Right hand catches the ball 1 coming down with a claw. This results in the right arm crossed over the left arm.
4) Left hand throws ball 3 (on right side), vertically.
5) Left hand comes to the left, catches ball 2.
6) Left hand throws ball 2, then catches ball 3 with a claw. Now the left arm is crossed over the right.
7) Right hand throws ball 1 (on the left side), vertically.
8) Right hand uncrosses, and catches and throws ball 2, catching ball 1 with a claw in the same arc. Arams are now crossed.
9) Go to step 4.
This trick is basically an entertaining combination of clawing and tennis, with a nice flourish for showiness. Especially fun with bright or even glowing balls.