I recently discovered you can flatten your tongue making it push into the teeth in each side. Is this recommended?
Hi,
no, you shouldn't push into the teeth. The tongue has to stay above them , on the alveolar ridges
nope
I have to force my tongue up there though so there is some pressure on my teeth to make room
Yes, gently and evenly apply pressure on the whole palate but do not touch the teeth if you can. Otherwise, depending on your age and case, you should consider to get a palatal ( probably skeletal) expander.
Don't get mad about "mewing", by the way . Don't think to much about it. It has to be natural , not forced.
This may help:
She says there shouldn't be air space in the mouth.
Basically if you correctly and entirely fill your mouth with the tongue, you SHOULDN'T BE ABLE TO MOUTHBREATH and the same time be able to breath through the nose