tongue position in shake
Since there is no silly question...
I started practicing shakes on my diatonic, still with much inconsistencies in the result (i.e. not always hearing a clear alternation between both notes involved), and I'm wondering what my tongue is supposed to do during the shake. I'm tongue blocking.
Should it stay put as it is placed to play the lower note and just stretch or lay a little wider to block that hole as I move my head to the right to play the higher note; or should it slide over the comb as I move my head to go cover the hole of the lower note in the same width as the precedent hole. In other words, should the whole mouth position slide up and down as one entity or should the tongue stay in the same spot, while the lips move up and down, and just lay wider to cover one more hole, then narrower.
And does that make any difference?
For a simple shake that involves two neighboring holes, you only need to move between those two holes.
You can move the harmonica and keep your head still.
You can move your head and keep the harmonica still.
But you do not need to change the positioning of your lips or tongue to alternate between the two neighboring holes.
However . . .
Some shakes are "dry" and others are "wet" and varying the size of your mouth opening can play a part.
A dry warble (or shake) plays each of the two notes separately, never both at once. So your mouth opening needs to be large enough to isolate a single hole, while you need to move so that you are playing either the right hole or the left hoe, never both at once.
A wet warble is one where the two holes are played together for some part of the alternation, so that in passing from one to the other you allow both to sound. At the extreme, you can just play both together and just sort of nuge to the right and left to emphasize each in alternation.
Wet warbles can benefit from using an enlarged mouth opening to facilitate mixing the sound of the two neighboing holes.
However, even with a wet warble, the mouth opening will stay at a fixed size as you move your embouchure relative to the harp. (Unless you want to get very fancy and move from a dry warble to a moist one to one that is dripping wet, in whcih case you might lightly widen your mouth opening as you make the warble wetter and wetter.)