The simplest device to use is the Breath Builder. Developed by the late Bassoonist Harold Hansen of Las Vegas, Nevada, the Breath Builder is a device used to feel the sensation of inhaling and exhaling. It is a tube of plastic [at least six inches tall] with a ping-pong ball inside. The bottom is sealed and the top has three holes drilled to vary the resistance.
To use the Breath Builder, place the tube between the teeth on top of the tongue. Next, get the ball to the top of the tube by either inhaling or exhaling, [which is easier]. Then hold the ball at the top of the tube while slowly inhaling and exhaling. The Breath Builder requires fourteen ounces of pressure to hold the ping-pong ball at the top of the column.
In use, visualize a string player bowing from frog to tip. Keep the motions of inhalation and exhalation as long as possible, increasing the length of the bow. Find the minimal function to keep the ball at the top. Look in the mirror and observe the body’s motions to keep the wind moving with minimal effort. Exaggerate inhalation [expansion of the body] and exhalation [contraction of the body].
Next, lower the resistance by closing more of the holes on the top of the tube. Go for length of breath and mentally increase the length of the imaginary string player’s bow.