"At a hastily called press conference, the exasperated Lombard allegedly shouted, 'Cock-a-doodle-do! Any cock will do!' out of frustration.
"Needless to say, due to the times, none of those present printed her words, but bad blood continued between Lombard and an outraged Louella Parsons until Lombard's death."
-- Jim Bacon, "Gable & Lombard: A Romance Made in Hollywood" (Parade Magazine, November 25, 1963)
Used by Eegra in their valentines day comic, where Bowser handed Peach a card with this phrase, and subsequently believes it is a sweet love message. Or something. Whatever the case, it's an exclamation yelled at a loved one that expresses ones awkwardness in a social or romantic situation.