Sit upright in a chair, keeping your wrist and forearm flat on the table.
Place the putty flat on the table.
With your fingers curled, place your hand over the putty, pushing your fingertips into it.
Straighten your fingers, pushing the putty directly away from you with your fingertips.
Your wrist and forearm should not move from the table.
Push the putty out as far as you can before relaxing your fingers.