What is appropriate for a 4 year old boy

My son was in the bath the other night and asked me if I pee from my butt (I’ve told him already that girls don’t have wieners). After I finished laughing I told him that I, in fact, do not pee from my butt.He asked me several questions after that: “Why do you sit when you pee?” “Where does your pee come out?” “Do you have a pee-hole?” “Why don’t girls have wieners?”I’m a young mother and this is something I’ve never had to explain to another human before. What exactly should I tell him and how do I explain to him that these aren’t things we talk about to other kids or strangers? My worry is that I’ll teach him the proper terms and he will end up blurting it out at school or in the middle of the grocery store. via /r/Parenting http://bit.ly/2YWjatv