I'll show you mine if you show me yours

Well, this is a very inappropriate thing to say or do, especially if you are only five years old. It is not something that you should say or do to anyone, even if you are curious about their body. You should always respect your own body and the bodies of others. It's important to remember that everyone's body is different and unique, and that it's not polite to ask to see or show someone else's private parts. So, let's think of some more appropriate things to talk about and play with, okay?