This is like a ball gag, but even better! There are two versions: for use with a strap (it has rectangular channel) or with the rope (circular channel.
It’s best to print it with rubber. Cannot be printed without supports.
By default it’s pretty big, about 40mm in diameter and 70mm insertable, but feel free to scale it!
the hole is ideal for 20mm strap or 15mm rope. Please, consider the fact, that after scaling it will change.