Too Young to Kiss
Concert booker Eric Wainwright (Van Johnson) is always too busy to see Cynthia Potter (June Allyson), a talented pianist. When she overhears that he has an open audition for children, she decides to pose as a twelve-year-old, under the name "Molly", to get his attention and advance her career.
The spanking scene
The film has a scene in which "Molly" gets a spanking by Eric (who still believes her to be a 12-year-old) for her bratty behaviour. The spanking takes place in the garden next to the swimming pool. Eric spanks "Molly" OTK with her own slipper while she begs him "Let me go! — Owww — Let me go..." The scene fades out quickly, but the spanking is implied to be a thorough one, as she is in visible discomfort when he puts her to bed afterwards. She is still sore the next morning.
Metro-Goldwyn-Mayer produced a promotion photo for "Too Young to Kiss" which shows this memorable spanking scene. However the characters are dressed differently and he spanks her with his hand. With Allyson dressed in girl's clothes, it's a rare example of an ageplay spanking in a mainstream film.
June Allyson (born 1917) was already 33 or 34 years old when she played this role.