For a 3 year old, the important things are to make sure she knows she can come to you any time she feels uncomfortable. Also, there's no need to go into detail

For a 3 year old, the important things are to make sure she knows she can come to you any time she feels uncomfortable. Also, there's no need to go into detail about it being a sex thing; you should approach it with the same level of detail you do the 'don't trust strangers' conversation. I knew that nobody should touch my private parts and mouth kissing was for grown-ups, like coffee, and if anybody tried, I should go find other adults + tell them. I couldn't have told you anything about why somebody would do that; I just knew there were bad grown ups, and that's about the level you're working with at 3 years old. There are bad grown ups (like whatever bad person in TV shows she watches), and if you find one, go get a good grown up right away. Emphasize most people are good and it's very rare, like how everybody in the family practices for a fire, and that we all watch out for one another. That sort of thing. (I don't know your parenting philosophy.) I'm assuming you have a neurotypical, potty-trained 3 year old; it's more complex when things like toilet-help are involved, I know.