Having my tongue rest on the bottom of your mouth. Proper tongue positioning is when you rest your tongue on the roof of the mouth and away from the teeth. It's been 2 years I've been "mewing"[1]. A good side effect for me: Now I stop snoring and I believe I have better posture. Some claim that it will improve your jawline but not for me, I guess I started too late. If I had started in my teen, I believe I would have…
”Mewing” is just normal tongue posture. It will not improve your jawline. Usually it’s the reverse: if you need to “mew” / put your tongue on the roof of your mouth consciously and if you naturally snores it’s because of a problem. Problem that is often genetic or more rarely that appeared during your development: either your face lacks forward projection or a part only is recessed (malocclusion: your upper and lower…
I'd also like to add that even in absence of sleep apnea, Upper Airway Resistance Syndrome, where the airway collapses but the body partially wakes up before it progresses into an apnea, is likely, and often missed by diagnostics.
In general, maxillomandibular advancement is always more effective than genioglossus advancement during genio.