"On 'Anyway, Anyhow, Anywhere,' during the solo, on the note A I would flick a harmonic, get it feeding back, and then go 'dit-dit-dit-dar-dar' with the switch. And by standing at certain angles I could get incredible sounds out of it, some of which were just characteristics of the Rickenbacker body, which I stuffed with paper. You could control it and it could be very musical. Certainly that sort of thing where you hit an open A chord and then take your fingers off the strings... the A string is still banging away but you're hearing the finger-off harmonics in the feedback. Then the vibrating A starts to stimulate harmonics in other strings, and it's just an extraordinary sound, like an enormous plane. It's a wonderful, optimistic sound and that was something that happened because I was posing — I'd put my arms out, let go of the chord then find that the resulting noise was better."
January 1, 1970
https://en.wikiquote.org/wiki/Audio_feedback