Mewing is the technique of flattening out your tongue against the roof of the mouth. Over time, the movement is said to help realign your teeth and define your jawline.

To properly mew, you must relax your tongue and make sure it’s entirely against the roof of your mouth, including the back of the tongue.

This will likely take a lot of practice, since you’re likely used to relaxing your tongue away from the roof of the mouth without giving it a second thought. Over time, your muscles will remember how to place your tongue in the correct mewing position so it becomes second nature. In fact, it’s recommended that you mew all the time, even when drinking liquids.

As with any DIY technique that seems too good to be true, there is a catch with mewing — it may take yearsto see results. Maxillofacial deformities are typically corrected with surgery or orthodontics, so you shouldn’t assume that you can quickly correct any issues on your own by mewing here and there.

One studyTrusted Source looked at tongue resting positions to see if any muscle groups were engaged as a predictor of long-term memory. In this case, researchers found that the 33 people in the study didn’t exhibit any signs of altered muscle activity.