Ok. I am here today to tell those of you that would like to learn a brass instrument the proper way to "buzz" on a mouthpiece. "Buzzing" is actually the vibration of the lips against the mouthpiece of a brass instrument. Without this "buzz," the instrument will not function, except to look pretty on your next concert.
Step 1: Tighten the lips and draw them back, as to resemble an "M" when you look in the mirror.Do not clench the teeth or keep your lips slack. It is important to learn how to do this without using your fingers to force the edges of the lips back. Good muscle control is very beneficial to this goal.
Step 2: Place the mouthpiece on the center of your lips while still keeping them taut.
Step 3: Blow a continuous stream of air into the mouthpiece with the jaws open slightly and the lips taut. You will find out that if you loosen your lips, even just slightly, you will produce a different, lower tone.This is true for the inverse (that is, tighter lips will produce a higher tone.) This is normal for proper play.
Experiment with different tones to build muscle control and stamina. With practice, you can be able to play a brass instrument properly.