I have a concern about my youngest son and cousin who are both 5 years old. They don't see each other often, but the last three times they were caught "experimenting". The first two occasions I stayed calm, brought them both down stairs and told my sister and her partner (who completely overreacted, sying things to his son like "are you gay" and "are you wrong in the head"). When they left I explained to my son that private parts were to be kept private, and so on. On the last occasion after they had left I asked my son exactly what the game consisted of. He explained that they were playing mum and dad, mum was dead and his cousin kissed his wee wee (our word for penis) and in the middle of his bum. My concern is for my nephew, is this possibly him acting out abuse or is it normal curiosity? I don't know what to do next, I've told the parents about the nature of the game.