I have no idea AT ALL where to start in explaining to DS (6) about this, and last night he asked the question - "what's sex?" because of a throw-away line on tv. He knows where babies come from, just not how they get there in the first place. He even knows about menstrual cycles, as he was 4 1/2 when DD was born, and talking about it seemed very natural at the time.
But we need help in telling him about the sex bit, as we really don't want to freak him out, but we don't want him hearing about it in a skewed way in the playground. I'd be very grateful for advice on how to approach this, and any recommended books.
maybe: when two grown up people love each other very much, they give each other a special cuddle and their private parts touch. This can make a baby. you may want to add later that it is an activity that people engage in for pleasure rather than just baby making
I'd just say "Sex is a special cuddle that only happens between grown ups who love each other very much and it's something you'll understand when you're older" I wouldn't add more unless he asks TBH. Keep it simple and factual
(I remember having a conversation with friends as a teenager and we all agreed that the "When a mummy and daddy love each other very much" line was universal, even though it was probably more like "When a mummy and a daddy drink a lot of wine and start feeling randy...")
I've never liked the term "special cuddle" though I know a lot of people use it, it's always sounded like a term that could be used by an abuser to make it sound ok because it's like a cuddle IYSWIM?
I'd go for a more accurate description of it being the way that a man and woman (who love each other very much, if you want....) can start a baby growing inside her, and that sometimes they also do it because it feels nice even if they aren't planning to make a baby.
Then if he wants to know "but what is it?" you can explain about the man's willy getting hard and fitting inside the woman's vagina.
I don't think children freak out at it, if you treat it as a matter-of-fact kind of thing rather than a big secret.