Watch the Tongue-Slapping online guitar lesson by Annie Raines from Blues Harmonica Blueprint
SINGLE NOTE TONGUE-SLAPPING: This technique employs the famed "Hakalugi principle" whereby you engage the central part of your tongue against your hard palate and make a light hissing "ghoo" or "ghaa" sound, then immediately thrust your tongue forward so it’s pressed against the back of your upper and lower teeth and alveolar ridge (that upside-down "shelf" behind your front teeth). The driving engine is the bulk of the tongue muscle coming forward. The motion feels as if you were saying "ghaa-with!" The tip of your tongue generally doesn’t touch the comb of the harp, rather it hangs slightly below or rests slightly above it, depending whether you’re an "overhang" or "underside" tongue-blocker.
TROUBLESHOOTING: Start by trying to get a 4 hole blow and draw. If you’re just getting the 3 hole, open your mouth wider. If you’re getting some of the 1 hole sounding out on the left side, try to block it out with your tongue. You might need to orient your tongue more diagonally towards the left side of the harp. If you’re bending the note, there’s too much tension in the corner of your mouth or your tongue or both. This should be a very relaxed, loose embouchure. Keep your teeth close together and try not to drop your jaw.