David's Tip of the Day: Tongue Blocking Tips - The Basic Tongue Block

Place your lips over a four-hole span, using a light touch on the face of the harmonica. Use the top of your tongue just past the tip (called the blade of the tongue) with a light enough touch that the convex shape of your tongue does not completely flatten on the face of the harmonica. Cover the left three holes with your tongue, leaving the right-most hole to sound a single note. Move the harmonica latterly—the focus is to generally move the harmonica, not the face or jaw.

Special Note for Lower Holes
To play hole 3, your tongue centers on hole 1, covering holes 1 and 2 and some of the wood to the left of hole 1. To play hole 2, narrow your mouth slightly and center your tongue on the wood to the left of hole 1, covering hole 1 and the wood to the left of hole 1. To play hole 1, your mouth is commonly over holes 1 through 3, covering holes 2 and 3 with your tongue.