...[w]hen Waller was performing a song, he often altered the lyrics and added asides that commented on a lyric or even the entire song, as he did at the end of “Your Feets Too Big,” which was written by Ada Benson and Fred Fisher (and Feets is apparently the spelling Benson and Fisher wanted, not Feet’s). After he had sung the Benson-and-Fisher lyrics, including “Your pedal extremities really are obnoxious,” he added “One never knows, do one?” Isn’t this an example of making a claim to authorship through elaboration?
(By the way, “Your Feets Too Big” was also recorded, years after Waller’s version, by Chubby Checker, who included Waller’s tag line, and, in 1962, by the Beatles, who did not include it. [Available on the CD The Beatles Live at the Star-Club in Hamburg, Germany, 1962.])