A shrewdly made documentary about the rise and fall of Plato’s Retreat, the infamous Manhattan sex club of the ’70s and ’80s. ? A lot of the patrons were suburban schlubs, and the movie does justice to their odd… normality. The least classy person there ?was owner Larry Levenson, a nudnick who ?made the nightly bacchanals feel as friendly — ?and about as sexy — as a bar mitzvah. American Swing drolly evokes this Romper Room of middle-class exhibitionism, with its petri dish of a swimming pool and its icky lasagna-?and-chicken buffet. Plato’s Retreat was a buffet of bodies, and the film catches the moment America could think that was tasty. A?