Asuming right hand hitter.
If a simulated pitch would be down the middle of the plate, then a good swing with the Pro Glider should produce the ball coming off the bat into the middle of the net. If you “cast”, the ball will go to the right of the hitter (right field). If you hook your swing or don’t get full extension the ball will go to the left. When you have perfected this inside ball swing you can now practice pitches that are not down the middle. If you do a soft toss, no matter where the ball is thrown you should hear only one click. Both glider hitting the stop and the bat hitting the wiffle ball.
To help hitter swing with an inside the ball approach:
Without a ball on the bat place top hand (right hand) on glider and slide it all
the way to the stop. Place bottom hand (left hand) up close to the top of
the handle. Now attempt to swing. If you cast, the right hand will not slide
down the shaft. If you do it correctly the right hand will slide down and the
slider and stop will meet. Be sure hands are not in a position that will get pinched
when slider and stop meet.
If you have any questions please don’t hesitate to call.