I think Eddie Murphy told the story. He had just completed a stand up comedy routine at The Comedy Store and Bill Cosby was in the audience. Afterwards, Cosby, who was then often seen as a spokesman for Coca Cola, berated Murphy for using too much obscenity in his act. Eddie later called Richard Pryor and told him about Cosby's lecture, and Pryor said "ah, tell him to go have a Coke and a smile and fuck himself!"