Consciously feel the tank with your up-side thigh and knee. The rest of your weight can go through the balls of your feet, into the footpegs, but keep the inside foot free enough that you can pivot your leg. When you make it to the track and you get used to your knee touching down, you will note that your leg can fold up and not impede your ability to lean further. Remember to keep your weight off the bars, so that your steering is unobstructed, and the bike can move around and correct itself. It also makes it easier for you to provide steering inputs. As you prepare for the next corner, put your weight through your legs and slide your butt across to the opposite side without bouncing on the seat or bars; it should simply be a smooth transition.