Today's classic cover is a subtle little number from Avon, circa 1951. Of course any erotic meaning you take from the title is entirely down to you. "Willy" is actually the name of the lady and she has to sleep in that contorted pose to stop her makeup from ruining the pillow covers.
Creative choice of character name is also apparent with the heroine's mother, Tennessee--not to mention a male character apparently called Homerette and another called Red White. Not to mention Tom Kitty and Fuzz. Oh well.
As is always the case, the content of the book are not nearly as interesting as the cover suggests.