Are you still wearing rubber bands? do they start to tighten too much? I hope so.
Place the balls on a hard surface, which fit well in contact, take the short and wide cylinder, and place it over your balls, now take the pestle.
I think you imagine what's going to happen.
take the pestle and insert it inside the short cylinder straight on your balls, it should pass us well, try.
Let's start using it for its real purpose, pounding those balls.
Start by simply slamming the pestle up and down on the balls, do it quickly and without too much force.
Do it 15 times.