Keith Richards wakes in the night to write down insults to say to Sir Mick Jagger.
The Rolling Stones guitarist "enjoys" quarrelling with the frontman but insists he jibes are never meant to be malicious just banter.
He said: "Mick and I joust all the time. From my end it's never been a fight.
"Mick's a control freak - it's necessary for him to believe he's Numero Uno, so most of the time I go along with it - unless I think he's making a really wrong decision affecting the Stones.
"Maybe we enjoy jousting with each other. I wake up sometimes in the middle of the night and jot down a line - 'I'll save that one for him.' "
Despite their rows, Keith, 71, thinks Mick, 72, is an "amazing" singer but wishes he would lighten up.
He added to MOJO magazine: "We're mates, and as far as work goes, I couldn't think of another frontman to back up. He's amazing. What he puts in there is a rare dedication. I think he has a lot to prove to himself but it's unnecessary, because he's already proved it all.
"It's like, 'Relax Mick, take it easy.' But Mick Jagger relaxing? That's very rare. He's one of those guys that has to be doing something all the time."