Try expanding the bottle itself by heating it up, but be careful when handling hot glass. I cannot think of a way to make the ping pong ball smaller, so this is your best bet.
The best thing for a wicket keeper (or any close infielder) is that you must, on every ball, always anticipate that the ball will come through to you. Keep your...
That would really just be a large spray bottle. If you were looking for a water gun with more capacity, I would recommend sizing up the whole project to larger...
