Hey guys, I'm a trumpet player still in highschool and planning to go to university next year for the trumpet. I am having trouble maintaing a steady tone while playing longer notes in the lower register (low c to middle c). I noticed that my jaw trembles when playing and that I am protruding it quite a bit. My teacher said this should not be so. I am having a hard time trying to readjust it and my emboucher just does not form well to the new way. If continuing to play with a stuck out jaw is there any way to stop it from shaking? Is it bad to play that way?