How to Nestle the Harmonica in Your Mouth
When you put the harmonica in your mouth, your lips have only one job — to direct air where you want it to go without leaking out. Part of that job is also letting the harmonica glide easily to the left and right to get to different holes. For now, your goal is just getting the harp in your mouth and gliding without air loss.
Try holding the harp between your thumb and forefinger and raising it to your lips. To get a good sound without letting air escape, your lips should form an airtight seal around the harp. The following steps can help you form a good seal:
Drop your jaw and open your mouth wide.
Place the harp between your lips until you feel the harp touching the corners of your lips, where the top and bottom lips meet.
Let your lips close gently over the covers.
Let your lips drape over the covers like a light fabric. Don’t curl your lips inward or clamp them down. You should be able to slide the harp to the left and right in your mouth smoothly without dragging your lips along for the ride.
Keeping your lips on the covers, close your jaw.
Let your lips stay relaxed. You close your jaw to get the moist inner lips in contact with the harmonica’s covers.
Open your jaw again so that you can move air through your mouth (this move was only to get your inner lips on the harp).