I just started mewing about a month ago and I watched most of the videos Dr. Mew has posted on YouTube. I think I have the proper form down and I thought I made progress, but I'm not sure if I'm doing the suction hold properly. I can suction just with my tongue on the top of my mouth but I also can have a suction where I suck up the muscle/skin (whatever it is) underneath my chin. Doing so improves my profile but I'm afraid that I might be making that part bigger by "contracting" the muscle when I suction. If I don't suction the part beneath my chin, my profile hasn't improved by much, it may have even gotten worse. Overall I don't see any real upward swinging of the mandible. Should I be doing one or the other?
I don't understand your case enough to comment but normally the only muscles that contract along with tongue in suction hold are the mastication muscles.
my story: http://www.aljabri.com/blog/my-story/