The examples you refer to are not the same thing, you are asking about 2 different things, the first one is trilling several notes one hand while holding down one note with the other hand. The other effect is what I refer to in the video as a “shake” which is very easy to do by holding down the Bb while shaking with the left hand.
yes of course but the technique is the same…
so, one of the ones I use a lot is:
play high Bb (bis key fingering) and trill the G note below it, now add the right hand playing F#, F and E. then go back up: E, F, F#
all while trilling the G (and holding down the Bb)
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