With an average cast, three over-lengthy segments and pedestrian camerawork, ass fucking doesn't get much more basic than this.  (At least there's some honest passion going on once in a while.)

Aurora takes Fontana's rod up the chocolate speedway for the "first time," but his sweaty butt blocks the action.  The proof is in the pudding, however, as evidenced by a nasty shot of his spoo dripping from her swollen rectum.