Mewing is a technique that involves holding your tongue against the roof of your mouth to improve facial structure and alignment. The idea behind mewing is that by keeping the tongue in this position, it can help to reshape the jawline and improve overall facial symmetry. Proponents of mewing claim that it can lead to a more defined jawline, improved breathing, and better oral posture. However, there is limited scientific evidence to support these claims. Some people have reported seeing results from mewing after several months of consistent practice. However, it's important to note that everyone's facial structure is unique and results may vary. It's also important to practice proper oral hygiene while mewing to avoid any potential dental issues. If you're interested in trying mewing, it's recommended to consult with a dental professional first.