Greetings,
I sometimes compare the forward position of the upper lip which directs the air into the flute headjoint, to the way a turtle appears. The upper lip lifts and moves forward, exposing the wet, underneath tissue of the upper lip as the lower lip slides into the pocket between the upper lip and upper teeth for maximum air speed and direction control, creating a downward slant between the lips.
The specific image that is in my mind is Cecil Turtle from the Bugs Bunny cartoons I first saw as a child.
You may view these cartoons here, for both your education and your amusement.
http://www.youtube.com/watch?v=JNRB5MlgHF8I hope this turtle image is useful for your embouchure formation.
http://www.youtube.com/watch?v=OSWjXvr4E1M&feature=related
Best,
Catherine
