It's a lot like this:
Take one of those fat crayola markers you used in elementary school, attach a grapefruit to the top of it and wire the whole thing to vibrate like an old school electric toothbrush. Then go draw on a surface that isn't flat and provides very little resistance.
All that aside, I really enjoy it. I will say that it's the outlines that are getting me right now. But I've only done 2, so I figure that the more I do, the better I'll get. Right?