This exercise is designed to help strengthen the sound quality of your second diddle. It involves two separate types of strokes.

The first stroke, which is marked with a "W" or a "—", involves turning your wrist to the "up" position, and making the stroke. As the stick hits the head we relax our fingers, and allow the butt of the stick to push the relaxed fingers down, as the tip of the stick rebounds up. Make sure you are not wrapping your index finger all the way around the stick, of gripping the fulcrum too tightly, as this will not allow the stick to rebound.

The second stroke, which is marked with a "F" of a ".", involves closing your fingers back around the stick, as you turn the wrist back to the "up" starting position.

Here is a great demonstration of this exercise by the Santa Clara Vanguard drumline