Jim Dickinson: They started running down "Brown Sugar" the first night, but they didn't get a take. I watched Mick write the lyrics. It took him maybe forty-five minutes; it was disgusting. He wrote it down as fast as he could move his hand. I'd never seen anything like it. He had one of those yellow legal pads, and he'd write a verse a page, just write a verse and then turn the page, and when he had three pages filled, they started to cut it. It was amazing!
If you listen to the lyrics, he says, "Skydog slaver" (though it's always written "scarred old slaver"). What does that mean? Skydog is what they called Duane Allman in Muscle Shoals, because he was high all the time. And Jagger heard somebody say it and he thought it was a cool word so he used it. He was writing about literally being in the South. It was amazing to watch him do it. The same thing happened with "Wild Horses." Keith had "Wild Horses" written as a lullaby. It was about Marlon, about not wanting to leave home because he'd just had a son. And Jagger rewrote it, and it's, perceptibly, about Marianne Faithfull, and Jagger was like a high school kid about it and he wrote the song about her. He took a little more time with it, but not much more, maybe an hour.
The way he did it, Keith had some words and then he grunted and he groaned. And somebody asked Mick, do you understand that? And Jagger looked at him and said, of course. It was like he was translating, you know?
They were unbelievable, the raw vocals. They both stood at the microphone together with the fifth of bourbon, passing it back and forth, and sang the lead and the harmony into one microphone on all three songs, pretty much as quick as they could do it on the last night.
from K.Richards. Life