"I was talking to Jimi while I was just learning vibrato on the guitar. I had learned to "pull" vibrato, but you can't pull on the first string, so you have to learn to "push" vibrato. I was saying to Jimi, "I'm just beginning to get that push vibrato." He said, "Yeah, you push against the weight of the guitar." And my eyes lit up. "Mother of God, that's how he does it!"
So you have to push and be conscious of the weight of what you're pushing against, not just pushing the string. There's nothing more annoying than somebody who has "panic vibrato," when they shake their fingers as hard as they can. Panic vibrato is the most annoying, unmusical thing you can think of. Hendrix's vibrato was so engaging, and it involved you and it was earth-shaking. When he said, "You work against the weight of the guitar," suddenly I was pushing stuff around in a big way. That was a wonderful clue."