The whistling book made its appearance in the episode "Go With Me." It is the book that Princess Bubblegum was reading her whistles from. She was using it to practice for the Whistling Choir Death Match Championship.
The whistling book made its appearance in the episode "Go With Me." It is the book that Princess Bubblegum was reading her whistles from. She was using it to practice for the Whistling Choir Death Match Championship.