As with everything else in Dog Training attention to detail is important as we have you now understand.
For the dog the way that you treat him, others would do the same, you define the protocol and acceptable limits.  Muzzles: As much as you may love hearing his begging, this will allow just the whimpering to get through (unless tight) and so shut up his yapping or complaints.
Gags: Something to fill his mouth when Master is not there. Hoods This can allow him to maintain focus where it is needed Masks: These can be good for both the Master and the slave. Nothing quite a Ski-Mask to add a little 'terror' to a scene. What normally goes with a black Ski-Mask, usually a knife and a kidnapping.
It also hides some of the intent that the Master has for the slave! | 
