From Deaf&Drum:

Finally, a place to put a drink or two, some spare sticks or mallets, your phone, car keys, wallet, IEM/Earplugs or whatever while you're playing.  No more kicking your keys off the drum riser or knocking over your water bottle while you're playing.
The Drum Buddy is the solution.  8" diameter x 3" deep and lightweight 3d printed out of ABS or PETG.  

Drum Buddy Bigmouth:

1 - 3.5” Drink Holder

1 - slot for phone w/ charging slot

6 - holes for sticks

1 - hole for drum key

1 - large space for keys, wallet etc

1 - hole for Sharpie

It will mount to a standard tom mount (L-clamp or cowbell mount) with the supplied tom mount bracket.

Note: This is a left handed model and is reversed, not only in compartment orientation, but also in mount placement. It can still be used in any type of kit, but in the typical spot under a hi-hat for a right handed kit setup, it would not be ideal.