I have been playing trumpet for around 4 years now, and i just switched to Euphonium a month ago under my directors recommendation because I have always had a embouchure problem on a small trumpet mouthpiece. I have made a big mistake by not playing on my trumpet on that month, since the Euphonium mouthpiece is obviously a lot bigger than a trumpet mouthpiece. Now i have jazz band tomorrow and I'm playing trumpet and I am a bit worried about what will happen. I do however have the time to practice trumpet today and obviously the bad embouchure is coming back to haunt me. Any help?