What do I do with a student who is not able to keep left hand thumb on neck when doing vibrato. It wiggles around. He has large hands and also complains about first finger hitting the pegs when doing Developing Violin Vibrato The Instrumentalist Amazon.com: 3 Rolls Violin Fingering Tape, 3mm Violin Finger Tape Cello Violin Fingerboard Stickers Finger Guide for Violins & Various Orchestral Instruments Fretboard Note Positions (Black) : Musical Instruments Can someone advice me if I'm practicing this vibrato correct? A concern is that my thumb keeps rotating while I vibrate with the second finger! Thank you so much in advance, Sepalika Silva