Some of the information is Boop-Oop-a-Dooping full of SPOILERS. Boop-Oop-a-Doop!
"Poop-Poop-a-Doop"[1], "Poo-Poo-Pe-Doo," "Poop-Poop-Pah-Doop," "Poo-Poo-Pa-Doo"[2] is an alternative ad-lib of "Boop-Oop-a-Doop." It was said to have been a scat singing style that was adapted by Helen Kane, with several performers claiming that they had done it before her, one being Chic Kennedy and the other being Edith Griffith, who had used the "Poop" routine a year before Kane in 1927. Kane later changed it to "Boop-Boop-a-Doop." Sometimes in the "Betty Boop" cartoons, Betty Boop's voice Bonnie Poe would do a "Poop-Poop-a-Doop" routine. In Betty Boop's debut Dizzy Dishes, Margie Hines uses a "Poo-Pah-Doop-Pah-Doop-Pah-Doop, "Poo-Poo-Pah-Doop!" and a whoopie patterned after the song "I Have To Have You".