If your cube pops frequently... don't use it ^.^" (or modify to fit you rubik yourself)
I'm using Dayan Lingyun (III) and it never pops.

Rubik belt mount
https://youtu.be/iNTrZaO57oU

Rubik mount on a belt
https://youtu.be/N-AazWSYb-E

CAD file on onshape :
https://cad.onshape.com/documents/87e9bdfbc788e10ad5a8d48f/w/172e9cb0f70be73d97a03e04/e/d37d50d35cc2438748919bce
remix if you need :)