For some of us, Downton Abbey is satisfaction enough. Though short on consummation, the PBS Masterpiece series is a triumph of class porn, period costume porn, castle porn, and zinger porn, with high production value and legit plot lines. For everyone else, there’s Down on Abby, the punny adult parody in which Lord and Lady Grabhem and Master Bates explode the sexual mores of interwar Britain in carefully non-incestuous pairings. Not recommended for those who get distracted by historically inaccurate details like squared-off French tips and thongs.