Chats with Mac

Mac and I chat as he finishes his chicken nuggets:

Mac: I hope I never go to England or France.
Me:  What?  Why?
Mac: I don't wanna have to drink with my pinky sticking out, and I don't wanna use the heiney washer.
Me: Your pinky.......um, a heiney washer?
Mac: Yeah, the one like a drinking fountain, only for your heiney.
Me: A bidet?
Mac: Yeah, that one.

How does my seven year old know what a bidet is?!