“SEX. Now that I’ve got your attention . . . ” Like the sales pitch that begins with that jokey advertising ploy, this exhibition, titled “Intercourse, ” didn’t have much to do with sex. In her statement for the show, curator Eileen Sommerman writes that the word “intercourse” denotes “communication or dealings between or among people, countries, etc.; interchange of products, services, ideas, feelings, etc.” This is broad territory for such a modest show, and the three works don’t really seem to fit into this formulation. But Sommerman’s strengths as a curator have less to do with exposition