This gag was a lot more complicated than the one for the wolf. Because we have flat teeth that don't interlock, a flat, solid section is necessary to keep them separate. Doing the same with canine and other carnivore teeth wouldn't work because of the angles at which the teeth interlock; it can be done, but it would require specific molding to the subject's teeth and tanking it in and out would become a bit of an issue.

Fortunately, for us and herbivores with our flat teeth, you can simply stick something between them.

This one inflates to fill the mouth cavity between the teeth as well as the cheeks behind and to the side, where the precious gag simply inflates the whole thing.

Note to other Blender users: No, I didn't use the new pressure feature of the cloth simulator. I felt it unnecessary for such a simple thing, and because the gag itself has so little geometry, I just used keyframed shape keys.

The actual inflation port is hidden inside the feeding tube and would require another special attachment to inflate/deflate. I might update the gag diagram, but it isn't really important right now and I want to finish the rest of the muzzles.

I shouldn't need a special thing for the other carnivore muzzles, so the wolf muzzle/gag should work for most other heads and mouths. I just need to resize the existing geometry to fit new heads.

Full size high framerate version available to patrons on Patreon here:
https://www.patreon.com/posts/37713560
The mp4 video file is "attached" to the post just under the description text.