I just did a quick google on it.
http://www.didgemusic.com/instruct/circ.html
All I can say is that I can't do it.

Although I CAN do it while blowing bubbles in my milk. (A coffee stir stick has the best resistance for this)
It's also not overly important. I find it intreging because it's one of the few techniques I have yet to learn.
Have fun
Eric
__________________
Eric Sproul
Practice is like filling a leaky bucket
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