THE LA MAZ
childbirth method has an exercise for sustained breathing,
meant to help with concentration during labor, of imaginging
that you are blowing out a candle....so you blow a tiny stream
of air at a candle which you imagine to be a foot in front
of you.

come to think of it i am not sure what that has to do with
having babies, but might help in controlling breath.

and the whistling deal might help in controlling birth,
also, cuz every one will stay away from you !!