| If you stretch your lips back, as in a smile, you will pull your lips to such a point that vibrations will cease.
Don't think about your lips, but think about your aperture, or the hole the air comes through. To ascend, you want the aperture to go from a Slurpee straw sized hole to a coffee straw sized hole. Of course, those sizes are completely arbitrary and probably not correct; but, the idea is to think about the aperture going from larger to smaller. This allows the air to speed up, when accompanied by proper support, letting you ascend into the upper register.
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--Matt-- |