Mommies please help me!

My daughter has found her private area and I just showered her and she said my butt tickles because I told her to dry herself . And I said what do you mean and she said my butt tickles and was laughing and then she pointed at her private area and I simply didn’t know why to tell her besides to stop doing that. I told her you don’t do that ok. And she said it’s my butt and I told her it’s her private area. And she just responded it’s my butt and it tickles so I simply told her it’s your private area and you don’t let no one touch that area ok? And she said aww why ( I think she thought she was getting in trouble) I just told her because no one is allowed to touch you there. Mommies help me out? My daughter is 4 years old. I just simply don’t know how to tell her beside what I told her.