My embosure is a real pain. I have been in this two year stump with my embosure. Everytime I go high (like to a high f or g and above) i put pressure on my top lip and this makes my mouthpiece slide down a little bit so it goes way down in the pink and it feels like only a little part of my lip is vibrating. Then when i decend im fine but my mouthpiece dosent go back it stays in the pink and its playable, but i cant go back up to a high f or above because my top lip just stops vibrating and this has been the worse thing ever. It has caused some terrible endurance issues and i am going to bring it to my teacher's attention asap, but i was wondering if anyone else has had this issue and how you fixed it. And ive been playing for 8 years and i play on a Bach 3C, so i dont think there is anything that the mouthpiece is doing wrong. Thank You for any Help!