Let them wear a muzzle: it trains obedience and submissiveness.
In this gorgeous piece, the inflatable butterfly gag also ensures that the wearer can't say anything more, because the inflated gag fills the entire oral cavity due to its perfect shape.
This sturdy muzzle with head harness is made of 3mm thick rubber, and fits perfect.
For more safety the buckles can be equipped for locking with padlocks.

The muzzle harness fits for a forehead circumference of 52cm to 62cm.
Sorry - the shown hood is not included.