The Stepmother (1971)

According to the myth of Oedipus, every boy child harbors the urge to make a cuckold out of dear old dad, but most sons balk at the idea of becoming motherfuckers, which is where The Stepmother (1971) comes to the rescue. The best thing a father can do once he has ditched the mother of his teenaged son is to hook up with a hot-pants broad who is young enough to be the boy's big sister, offering the kid as much guilt-free, taboo-tinged erotic adventurism as he is willing to shake his stick at. With a cast peopled by soap opera stars of the day and nudity quotients as set by the sexually suggestive standards of 1970s drive-in fare, The Stepmother delivers multiple eyefuls of fine femmes in fancy undress.