Step 1: Holding the Jews harp
Now, grip the edge of the rounded end firmly with your index finger and your thumb like in the second picture. You do not want it to slip or move at all so apply about the same pressure as if your were Vulcan neck pinching someone.
Make sure the no part of your hand or fingers are touching the thin piece of metal in the center, because it has to vibrate freely.
Step 2: Positioning your mouth
If your harp slips up or down while your plucking it,the vibrating middle part could hit your teeth and that can be painful.
Now slide your teeth out to the open end of the bars so there is a space between the corner of your mouth and the end of the bars. This will make the sound a lot louder.
Now hold the harp firmly against your teeth. This is important because when you pluck the middle part it will make the whole thing vibrate and if it's not tight against your teeth it could give you whiplash and possibly damage your frontal lobe.
Now let your lips relax and rest on the bars.
Step 3: Changing the tone
Once you get that, pluck it again and change your mouth like your saying "Eee".
You can make "Boing" sounds be changing between "Oh" and "Eee" quickly.
Now try Breathing in and out through your mouth in rhythm to your strumming and it will change the sound a little.
Now experiment and have fun!!