With teeth, comes dental hygiene.
Bernard loves having his teeth brushed. This procedure consists of me placing a tiny molecule of toothpaste onto his miniscule toothbrush, and then sticking it in his mouth and attempting to brush his lower front teeth (which are the only teeth visible, at present). I listen carefully for that lovely sound, oh it’s one of the loveliest sounds in the world, I think, the sound of teeth being brushed. That sound means that I’m brushing teeth, and not just tongue.
Bernard, meanwhile, is co-operative in many ways, but not in others. Like my late cat, Chippy, he loves the taste of toothpaste, and attempts to devour it. The upside of this is that he allows the toothbrush in his mouth. The downside is that, to him, eating toothpaste is the priority, so his actions are not geared towards the brushing action, and often go directly against it.
He also makes cute burbling sounds and allows foamy toothpaste to dribble out of his mouth like a cross between a rabid dog and a volcano.