Shelley the Singing Sitter is a babysitter who advertises on the Extreme Sitters webpage. Her video presentation shows her wearing hippie clothes and playing the guitar. She sings “If you’re naughty and you know it you should stop” to the tune of “If you’re happy and you know it”, looking very insecure as she does so.
In Mind Your Manners Mrs. Tibble decides against hiring her because the twins see the video and immediately want to put putty in her shoes.