A number of people have expressed an interest in the types of isometric exercises that I recommend for use when you must be away from the horn.
Here are a few ideas which I hope you'll
find to be useful in maintaining and developing your chops when you can't
take the time to practice:
a). Roll your bottom lip out as far as possible.(Try to touch your chin with it). Be sure to keep the upper lip in contact with the inside of the bottom lip as you are doing this. Hold in the extended postion for a count of ten, then gradually roll the bottom lip back up, so that it is hugging the outside of the upper lip. Rest. Repeat.
b). Purse your lips as far forward as possible. Hold for a count of ten, then gradually relax them. Rest. Repeat.
c). Roll your lips inward, so that the red(membrane) of your lips disappears. Be sure that both lips are in front of the teeth as you do this. Hold for a count of ten. Rest. Repeat.
There are other exercises which are also beneficial, including that of bouncing a small paper tube between your lips(but, again, in front of your teeth--gripping the paper only between your lips)...With practice, you'll eventually be able to do this with a pencil or pen...
Finally, there is an exercise which I do all day long (when I'm not playing) which is difficult to describe with words, but creates a sort of a squawk when done correctly....Roll your lips slightly inward, then use your tongue to force air through them, stopping the air by having your tongue close against the roof of your mouth....With practice, it's possible to play chromatic scales this way, and it's a good way to prevent the dreaded *braccck* attacks, since your lips become more accustomed to placing pitches very accurately....
(this is based on a post Jeanne sent to TPIN)