Using medium force, smack the clay ball as close to the center of your wheel’s bat as possible. Brace your right elbow in the crease between your leg and torso or against the inner surface of your thigh.
With the wheel at full speed, wet your clay with water or slurry. The clay must always be lubricated. If it dries out and grabs at your hands, the friction will cause the clay to go off center. Tuck the loaded sponge between your left palm and last two or three fingers. Squeeze liquid out as needed on both interior and exterior surfaces of the pot.
Push the clay inwards toward the center of the wheel head with your right hand. Use your left hand to push the clay downwards. Feel free to push your clay up and down a few times. Some potters believe that this helps compact the clay even more and aids you during the throws.
The clay is centered when you can lay your finger or hand against it and the finger does not move in any way. Visually, it will look as if the clay were still, even when it is rotating at full speed.