Knee Rouging
While watching Chicago, you might have caught the lyrics, "I'm gonna rouge my knees, and roll my stockings down. And all that jazz."

That's not just a weird lyric — it was a major fad during the Roaring Twenties to rouge one's knees. While dress hems would hit flappers below the knees, that part of the leg would usually expose itself while they Charlestoned inside dance halls. So by rouging them and rolling their stockings down, it only brought more attention to that illicit flash of skin.