I strongly believe that every flutist has to develop flexibility of the lips. Playing without tension of the lips (or more correctly, with the right tension at the right place) and being able to move the lips forward and backwards freely while playing, in a controlled way, will improve immediately various aspects in your playing.
• Improve your tone quality
• Improve your intonation and intonation control
• Improve the transition between intervals and allow very smooth slurs playing, without unintentional accents
• Improve your control over your aperture and therefore broaden your range of colors
The following is an exercise that I created for my students. It only takes a few minutes each day to practice, but even that short amount of time will help flutists attain better control of the embouchure quickly.
Lip Flexibility Exercise
• Play the exercise at a slow tempo, in order to gain control over your lip movements.
• Play the rhythm precisely in tempo.
• The movements (forward and backwards) should be gradual and slow. Avoid sudden or quick movements.
• The lips should move forward in order to change to the higher note.
• The lips should move backwards in order to switch to the lower note.
• Anticipate the lip movements. That means that your lips should start moving before the change of the note.
• The aperture (opening in the lips) should not change through the intervals and the lip movement. Make sure the higher note is as loud, open and rich as the lower note. If it isn’t, it is probably because the lips are pressed too closely together, and the aperture has changed size.
• Don’t over practice the exercise. Once a day from B natural down to G natural should be enough.
• Apply the same movements to various intervals you find in the pieces you are currently playing.