Randomly, I came across a couple sets of videos online; this youtube channel named "Orthotropics" by a Dr. Mike Mews. Where the guy suggest that adults with underdeveloped jaws, chins, and more narrow or elongated faces are not a matter of genetics but that of muscles and correct posture within the mouth, the posture of the tongue. It is also suggested that people with crooked teeth suffer due to not performing this action which is suppose to support the upper jaw.
He suggest that individuals should live their entire lives making sure that their tongues rest firmly at the roof of their mouth, touching the hard palate, with upper and lower teeth in contact, breathing only though the nose. He also suggest that mouth breathing is unhealthy for an aesthetic face and causes a slow elongating of the face. I've never heard of anything like this before and have found it interesting. Personally, as a child, my parents would scold me if I sat around with my mouth hanging open, but I've never made a habit of resting my tongue at the top of my mouth as Dr.Mews suggest.
Here is how the position should be, based on his ideas.
Video - https://www.youtube.com/watch?v=WmZZfO0hXLo
What do you guys think? I'm going to try it.