Sean Highland likes to show his donuts off during freeride shows. He does them on a 426! (can't stand the guy, but he's hell on a thumper!)
I've done em on my 125, but I hate to wear tires out for no reason.
Stand as close to front as you can, lock the front up, spin and lean just a tad....once youve got it starting the circle, just use your body english to keep it going around. It's a feel thing. I've seen a few hold the front controls from the underside for this. I find that a bit hard to do, but it seems they can hold the brake better whilest spinning.
Speedymaniac, feet on the ground..NO FAIR! :)