Trumpet players know this story all too well.... To get those screaming high notes, there is a natural tendency to push the mouthpiece HARD against the chops. Often times too hard - to the point where you regret it later. Players know that more mouthpiece pressure can help to support weak or tired chops in order to continue playing. The downside is that too much pressure against the lips prevents proper blood flow, and you wear out even faster - and finally it's game over until you've had plenty of time to rest.
This will prove invaluable tool for my students who I believe are using too much mouthpiece pressure.