AHH the mouth…This was difficult…To grasp really…

Essentially I figured out that the mouth is really a swollen snake area for the top lip that bulges way out, & the lower lip is another swollen snake that bulges out, & in the middle is a hole that needs to be coloured black too to make it look even deeper…

Once you understand that whole mouth idea you can sort of muddle along in Edit Mode…At least I did…

Grabbing a line of edges & faces along that might be an upper lip then using the Push/Pull tool to make it bulge out…

Same for a lower lip bunch of faces…

Grab that center area between your two lips & push it all backwards to make that hole area…Colour that hole area black to make it look even deeper…

Then, using the Shape Keys method described in the previous post, in Edit Mode, Move your Lips into a closed position, setting that closed position with your Shape Keys…(In Vertex groups)…

So now you can animate your mouth! Using the shape keys value slider, open or close it & insert key frames for each pose…(Hover over slider bar & press “i” to insert frames…)

For fun, now that I sort of know how, I made one eye wink…See the previous post for more about blinking…