[solidwalnut]

Carol--

I forgot to mention a third basic type. This might help out. It's the type I use on the acoustic, mostly (I typed the first response at work this morning and it didn't come to mind!).

The type is a cousin to the wrist shake one. But instead of the finger and hand remaining steadfast while shaking the wrist, the hand and wrist remain steadfast while shaking the finger.

Start slow and you'll feel/hear the effect. Pick any note on the B or E string in any fret using any finger. Play the note, and now put slightly more pressure on the string and pull it down slightly and then release it (keep it fretted). Increase the speed. You can use this to great effect. Hope this helps.

Steve