quick on one's feet

— The lightest moment of the night came before its heaviest, when Macca began “Blackbird” but screwed up a lyric, singing “take these sunken eyes and learn to fly” instead of “take these sunken eyes and learn to see.” The Beatle was quick on his feet, pointing a finger of blame at the man who’d been to 146 shows. “Let’s start that again. Oh, God.”