This is a very nice looking trick, in which you juggle 2 clubs in one hand, and use the third to knock back each club as it reaches the top of its arc. The knocks must be judged so as to reverse the clubs' spins, and allow them to be caught again.
The 'knocking' club should be held horizontally, at approximately eye-level. The point of impact for both the club in your hand and the club in the air should be at the top of the handle, not on the body.
The 2 clubs that you are juggling should be thrown high, with slow spins, as though you were doing 2-in-1-hand on single spins. Strike them slightly after they become vertical, in this way the club is pushed up as well as away, creating more time before it must be caught. Very little force needs to be used when knocking, it is almost sufficient to hold the club still and let the others rebound off it.
Practice with just 2 clubs at first - throw one and knock it back with the other. Next, try to incorporate a single knock-back into a cascade, and lastly, do the trick continuously with one hand.