Keep the Seal
Within "the perfect circle" (the rim of the mouthpiece itself), a hermetic "seal" is formed, much like the head of the tympani. When the mouthpiece pressure is neutralized by the puckered resistance of the lips, this "seal" is kept in place as the mouthpiece remains "the perfect circle", not slipping or sliding from its original placement position while ascending or descending, chromatically or making intervallic leaps. If this "seal" is broken, even during inhalations, the embouchure itself will not develop due to this disruption of "setting". That is why, during embouchure development, one is instructed to "use more mouthpiece pressure against the lips during the inhalation than during the actual playing".
Since we all are teachers, whether ultimately "our own teacher", teaching others privately or teaching the youth in a school setting such as Middle School, High School or College level, I will be gearing FixYourBrass to include teachers and performers. My posts will have various "topics" (Range, for example), with information for development and maintaining these categories as well as problems that may arise. The posts may be followed by my own "comments" and as to solutions to these problems watch for follow-up posts. So please add your own comments as to create a dialogue regarding said posts as well as any "personal problems" that I can help with. Looking forward to this exchange.