Что это?

A covering for the head of a mallet.

Где его найти?

The music room, or bring your own!

Как мне его использовать?

Use material to cover the head of your drumsticks or mallets to help reduce the noise level in the classroom. There are silicone or rubber “practice heads”  that you can buy to put on your drumsticks, or you can DIY by adding some duct tape, foam, cloth, cork stopper, etc. to the tip of the mallet to muffle the sound. For bucket drumming, you can also add a sheet of silicone to the top of your bucket to reduce the volume of the drum.