This trick is also the basis of learning to juggle four balls, so be sure you practice it alternating hands, rather than concentrating on your dominant hand.
This trick should be performed with the same type of smooth, scooping motion mentioned in the first step of the simple cascade instructions, except you aren't passing to your opposite hand. Be sure you're tossing the balls across your body, not towards your body, as it is easier to judge the catch this way, and it looks more impressive to an audience.