Tear off a thin strip, place it under your lower lip,
and blow gently over the top.
As you blow over the top of the paper, the paper curvature causes the
flow from your mouth to curve. As the flow curves (and the streamlines
curve) the local pressure decreases (from Euler's n-equation)
and the paper experiences lift. As you blow harder, the turbulence
in your blowing can clearly be seen by the fact that the paper
is flapping unsteadily.