[NSFW] Teen using porn for "birds and bees" lesson, what are your thoughts?

If you were at a family function and on the way to the bathroom you spy a male teen relative in the den with a female classmate and on the laptop a pornographic scene is playing, and she is describing how babies are made in very clinical terms; she keeps prodding him “You got that, right?”, and “You understand?” as if she wants to make sure he got what she is telling him. What would you do? Would how or where they got the adult content play any relevance or not? Would you believe porn was a good use to help describe human sexual biology? Would you praise her for giving him ”the talk”? Just how would you handle it?