From @mami_and_morty: “Mami is chewing some serious invisible gum tonight! I have no idea why she does this but I love it so much!! 😭🐱❤️” #catsofinstagram [source: https://ift.tt/2AtevFX ]
I’m wondering if this might be some type of residual suckling reflex? It looks like the correct motion, and it makes sense that it would be paired with kneading while being pet. Kittens suckle when comfortable and secure, so it could be that this behavior is the last of a kitten-hood behavior that never was fully extinguished. That’s about the best I’ve got, because I haven’t seen this before either!