I've never walked in on my parents having sex, but I imagine it's only slightly more traumatizing than watching an episode of Game of Thrones with them. 

HBO, it's not porn, but it's really close and exactly the reason that Sunday night should not be family TV time. (Unless you enjoy watching cousins getting their freak on with your parents in the room, and if that's the case -- seek therapy you perv.) HBO Go rolled out a series of NSFW ads that are probably the most convincing reason ever to subscribe to the service.