Andy Cohen, the king of asking wildly inappropriate, tenuously related questions that everyone secretly wants to know the answers to, had John Slattery (“Mad Men“) and Rashida Jones (“Parks & Recreation“) as guests on “Watch What Happens Live” Monday night. True to form, Cohen used a proclivity of Slattery’s former “Sex and the City” character as a launch pad to ask him which celebrity he’d most like to pee on.  His more-bashful-than-Roger-Sterling-could-ever-be response above.