Spanking the Monkey (1994)

Bright young student Raymond Aibelli is forced to sidetrack an important medical internship because his mother, Susan, is recovering from a broken leg. When he isn't tasked with the most mundane aspects of Susan's recuperation, Raymond finds distraction in a neighborhood girl, Toni Peck. But, as Susan begins relying on her son for both physical and emotional needs, Raymond starts developing disturbing and unwanted new yearnings.