How to talk to children about "private parts"

[mostlycheese]

DS1 is 3.5 and has just started nursery (at local school). I'm thinking at some point we should be having a conversation (or probably several short ones) about how his private parts are only for him to touch/look at whatever. But I'm struggling with exactly what to say because I know he takes things very literally, e.g. I still wash him in the bath - should I stop doing that? Or will he understand that's ok? Also, a doctor may occasionally need to examine him (he had surgery in that area a while ago) - so do I mention that's ok?

I would like to keep it simple!

What does anyone say to their DC on this topic?

I don't go into descriptions...when he talks about his bits and pieces to you, then take the opportunity to just casually mantion that they are private body parts and only for him...that nobody else is allowed to touch there, except maybe Mummy in the bath or the doctor if Mummy has taken him to visit...that's what I said. I reiterate it now and then when they mention their genitals.