Circles and other slow wheelies are the hardest to learn. Im still learning circles, in fact. These are all about trusting your tires and getting into a groove. Once you get into a groove, its all brake and throttle control. Again.
There are three different ways to do circles. Some guys ride on the regular pegs; some with the left foot on the left passenger peg; or some with the left foot on the 12 bar. I use the second method, with my left foot on the passenger peg. I havent done too much with my foot on the bar, but I think there is an advantage because youve got more leverage on the back of the bike. You can use your body weight more to control the height of the tire.
To initiate a circle I clutch it up with my feet already in position, bringing it up like a 12, using the rear brake. For circles (and no handers too) Ill turn the idle up to 3500 rpm, so I dont really have to worry about the gas. But with the idle up that high, and your bike so high, if you dont use the rear brake youll loop out.
Once you get the bike up there, all youre doing is using body weight and the rear brake to control the wheelie. You initiate the turn by bending the inside knee and shifting body weight into the wheelie. You want to keep looking into the wheelie, because you go where you look. You keep it going by blipping the throttle and tapping the brake. The gas makes it run wide and the brake tightens the circle upthe same concepts as with cornering on a roadracing track.