Pick up your jaw harp in your left hand as shown in the picture.There are two ways to hold the jaw harp, depending on the shape of your instrument. For a harp shaped like the red one shown here, put your thumb on the back of the harp and your index and middle finger on the frame and hold tightly.
Make sure the metal tongue or twanger is pointing away you.
If you have a more rounded harp then you need to hold it with the index finger and thumb wrapped around it. The main thing is to have a good, firm grip so you can press the jaw harp firmly against your teeth.
Don’t do that yet, though. Hold the harp in front of you. With the tip of the twanger (that’s the flexible metal strip in the middle) pointing away from you. Put your index finger on the tip and pull it straight back toward you and let it go.
The faint sound you hear is what you will be amplifying with your mouth.
Now, spread your teeth about 3/8 inch apart and put the harp tightly against your front teeth. You might want to do this in front of a mirror so you can see what you are doing. You have to spread your teeth 3/8 inch apart so the metal twanger can pass between your top and bottom teeth.
The teeth should be sitting on the beveled edge of the harp…not the top, but on the beveled edge. Press the harp very firmly against your teeth. It is essential that you press the jaw harp firmly against your teeth with your left hand, otherwise it vibrate on your teeth and feel uncomfortable and not make much sound. Also, keep your tongue out of the way.
Make sure your lips are not stretched over your teeth. The metal frame must be directly touching your teeth.
With the end of your pointer finger, pull the twanger back TOWARDS you and let it go. IF YOU PULL IT TOWARDS YOUR FACE IT CAN’T HIT YOUR TEETH. Be sure and keep you tongue out of the way. When you let go it should have made a twanging sound.
Be sure and pull the twanger straight back, don’t push it to the side or flick it downward. Pull it straight back and just let it go to get the spring action of the twanger.
It is best if you put your teeth near the open end of the harp. It will be easier to play and you’ll get maximum sound.
To get more sound: Bring your lips around the harp so that they touch the metal frame but not the twanger. This will help focus the sound.
Now, for more volume and rhythm, very lightly breathe across the harp as you play it. For different notes move your tongue around.