Creators online claim mewing is the easy hack to define your jaw treatment-free. It involves pressing your tongue to the roof of your mouth with your teeth lightly touching and your mouth closed.

Mewing was invented by British orthodontist John ... other facial bones and soft tissue," said John Callahan, president of the American Association of Orthodontists to the Washington Post.

Mewing — an oral exercise that is touted as ... other facial bones and soft tissue, said John Callahan, president of the American Association of Orthodontists, adding that the organization ...