How to “shake” fingers while playing a note on the violin or viola?

☻☺♥ Mystery Girl ♥☺☻: How to “shake” your fingers while playine a note on the violin or viola?
I play viola and my music teacher never taught us how to “shake” your fingers on the fingerboard while playing a note…What does that do? How do you it?

Answers and Views:

Answer by simplistic_wonders
okay.
first, it’s called vibrato.
I have no idea how to teach it; “my” students already know how.
try googling how to do vibrato or youtubing it.

Answer by RU Violin
Resources on Vibrato
https://beststudentviolins.com/PedagogyTech.html#5