When the dough has reached about 8 inches (20cm) in diameter, you can quickly move your left fist in an arc that goes backwards towards your face. Do this while twisting your right fist forward away from your face. If you give a a little push upwards with your right fist the dough will spin like a Frisbee. Practice how it feels to balance the force of the fist twists equally. This will keep the pizza from spinning off into the corner (or worse).