Position of Mouthpiece on the Lips

Some more excellent techniques for learning the trombone.
The mouthpiece should be placed in the middle of the lips, two thirds on the lower lip and one third on the upper lip. This is believed to be the best position for the trombone player. The lips must never be protruded. On the contrary the corners of the mouth must be drawn down, enabling a freer, more open tone production. When the lips begin to tire the performer should never force the tone. He should then play more softly, because with continued loud playing, the lips swell, and it becomes impossible to emit a note. The performer should stop playing the moment the lips begin to feel weak and fatigued as further playing can be damaging to the lips.