Alan "Crunchy Frog" Morgan, wrote the following, I believe
This works well (it should, as you mention it is the analogue of three balls). Another thing I found *really* useful was doing 2 balls and a club. Start the 2 balls off together (right) and the club in the other hand (left). This lets you concentrate on club throwing/catching only 1/3 of the time. You need to use heavy balls to do this trick (so that the weight of the club and the balls aren't too different). Later you can try 2 clubs and 1 ball. After that..... need I say more?
The start with clubs is IMHO really important. Too many people hold one club in their hands and sort of let the other one dangle between their fingers like a spent erection (I know people appreciate these charming metaphors). I can attest to the fact that it is possible to grip 4 clubs firmly (*) so your hands *are* big enough to do it. The technique I use looks like this. Looking down at your right hand you see the club shafts go
1 2 \ \ / / \ / / / / / / \ / / \ \ OO/ \OO <- bulb of club OO OO
throw the clubs 1 2. Yes, I know that 1 is underneath 2, but it is rotating in such a direction that it slips out from underneath. Try this a few times. This lets you grip both clubs firmly and have full control over where they go flapping off to.
(*) ObUnneccessaryEgoMassage: I can attest to this because I am working on 7 clubs.