Delightfully naughty.

oh murr. i do love the gummed up muzzle

Which of three? The red one with zipper, the blue one with removable hatch or the black one with lace?

the grey one with the what looked like pink gum ^^

Ah! Muzzle in sense of snout! Now I get it! That's a bubble gum gag. Ispired probably but that cartoon of Tom And Jerry where Jerry freed the big grey dog (whose name is always changing) from the dog catcher and in exchange the dog offered his aid whenever Jerry had whistled for.
So, after many beats from the big dog, Tom decided decided to be smart and, pretenteding to be friendly to Jerry, he offered him a bubble gum covered with glue. And Jerry fell in the trap