There are 2 basic ways to get 'a lot of notes in a short time' from many instruments.

You can finger the notes while either letting the 'exciting action' run, or stop/start for each note.

On the violin/fiddle, this is done with the bow (the exciter).

On the tin whistle, you can tongue each note (stop/strting teh exciter - the breath), or just let the fingers do all the work while the exciter keeps going. It's actually easier to not tongue while doing trills, 'slid notes', cranning, etc.