good tongue posture is what we were meant to all have and we need it if we want to become the best version of themselves. its just as importatn as body posture. and it fixed my tmj

I think the best approach to helping tmj is just proper oral and body posture, i.e. mewing. Chin tucked, head back, posterior third on soft palate spread out laterally to touch the back molars, teeth together but not toucing (maybe 2mm apart), lips together, chest up, shoulders back, feet hip width apart facing forward. If you do all these things and maintain for as long as possible you should lessen TMJ symptoms. Also, if you have TMJ issues, don't "hard mew". Just let the tongue *rest* on the roof of the mouth for posture, don't be pushing 24/7 because that will stress the masseter muscles and inevitably cause TMJ pain.

What if your tmj is compressed into the joint and that's causing headaches? 

I tried mewing but it started to give me a huge headache because my jaw disc is displaced and it's pushing my mandible too far back. Should I wait for an appliance to keep my jaw in place (where it's not compressing so far back) and then start mewing? 

That’s amazing! Did you notice changes? There’s all these appliances but I feel the body can heal itself along with possible cranial work for any trauma or misalignments 

Yes its sooo confusing. I do not have jaw pain though but often feel uncomfortable in my body, maybe facial area feels fatigued a lot. Are you tongue tied at all? It seems many are in some way and that can also cause jaw pain, headaches, etc... I feel like mewing should help the lower jaw come forward but not 100%