Miles recently began to say "fuck" a lot. When I was eight years old, my parents did not try to get me to stop swearing. When my friends were over, and I swore in front of my mother, they were always stunned that nothing happened. But I had enough understanding of linguistic register to know that I should not swear at other people's houses, because their parents would get upset, nor did I swear in the schoolroom (though of course I swore, as all the other kids did, on the playground and at recess). So I could see trying to just ignore Miles's swearing, but for two things: first of all, Andrea does want to get him to stop, and secondly, I find it annoying, too. I am retrospectively impressed by my parents' patience with eight-year-old me.
One thing Andrea pointed out to Miles was that he did not even know what the word means. So of course he wanted to know! I figured, he's eight, he can handle it, it's time to tell him about babies and sex and all that stuff. So I told him that "fuck" is a word that is mostly used as a way of expressing intensities, or as a way to shock people, but that it also has to do with how babies are made, etc., etc. In the process, I told him that you can also say "make love" or "have sex" for this "real" meaning of the word.
So then a couple days later, Andrea said something to Miles that he was quite surprised by, and he responded, "What the have sex are you talking about?"