No foul language

Ground situation: 1) In the last couple months both girls have had what the ER doc's taught us to call "straddle injuries."  Yeah.  In varying degrees from awful to worse.  Stitches in one case.  Let that sink in a moment.   The term turns out not as euphemistic as it sounds.  It's quite accurate, actually, and you don't have to keep saying "when I took a monkey bar to the who-ha."  We got climbers and jumpers and generally fearless girls.  And they are twins so they do freaky twin stuff like hurt themselves in the same way, weeks apart.  2) Our approach to profanity is outright relish to  grudging acceptance.  There just doesn't seem (to me) to be much integrity in forbidding language.  I'm an English lover/teacher.  And I'm profane.  Heather's thing is: be honest as the age will allow.  We reject the notion of bad words.  Words are good.  Period.  The thing to learn is when and how to use them.  No bad words, only bad times/uses of words.  You can imagine the eyebrows this raises, perhaps even your very own, as our kids sort out the rules. . . of usage, as it were.  You may disagree, you are free to, and it will probably make the story better if you do.  What follows is pretty much verbatim a conversation we had in the car on the way to school last week.

That Adele song comes on, "Set Fire to the Rain, watch it burn..."
Adders: dad, what's she singing about?
Me:  Uh.  Um.  I think she's angry.  She's imagining. . .
Wyatt:  No, she's sad.  She's sad.  This is a sad song.
Me: (quick peek in rearview): okay, yeah, sad, but so sad she's angry too and imagining...
Wyatt: there are SAD songs and MAD songs.  I like mad songs.
Me: Sure.  Mad songs are fun.  But i think. . .
Wyatt: This is a SAD song
Me:  Yes. It's a sad song.  No doubt.  But. . .
Wyatt: you said, you said she was angry.  That's a MAD song.  This is a SAD song
'Nother rearview check: six eyes, waiting: mad or sad, dad?
Me:  Sad, yes, you're right. but there's anger in her sadness.  She wants to set fire to the rain.
Ags:  how would you even do that?
Me: well, you wouldn't, you couldn't, but imagine being so sad AND mad that you thought of it. I think that's the song.  Raindrops could be like "tears" [I hate the finger-quote thing, for some reason I do it here. I don't know.] and you don't want to cry them, you'd rather burn 'em instead. (Kick save and a beauty)
Rearview:  knowing nods.  Sage, dude, very sage.
Ags: Why do people do this: she does the finger quote thing "--"
Me: that's a good one.  It's a way to indicate you don't really mean what you're saying or you mean it in a different way.
Rearview: stone faces
Me: Like, Ags, if I asked you how your "boo-boo" was.  I do the finger thing so you know that i know it's much worse than a boo-boo.  It's a serious injury.  But i can call it a "boo-boo" with my fingers so that i can protect your privacy and I dont have to keep asking you how your vagina is.  which might get . . . does this make sense?
Wyatt: kinda.
Me: Ags?
Ags: yeah (not very sure)
Me: but there are lots of reasons you might want to hide your meaning.  Not your meaning.  Not hide it.  Disguise it. Or, there are lots of situations you might want to say one thing and really mean another.
Adders: why's she sad?
Me:  I don't know,  . . . maybe it's an adult thing.
Wyatt: Well, she's only 22.
Me: okay, but she's older, lots of things could make her sad. what makes you sad, Adders?
Adders:  I was sad went I got hurt.
Me: yeah
Adders: and when Ags got hurt.
Me: yeah.  We all were. i'd like it if you guys didn't go your whole life twining injuries. one was enough.
Wyatt:  MAD songs have curse words in them
Me: they do.
Wyatt: Like Green Day songs.  Billy Joe Armstong swears A LOT!
Rearview: general agreement.  song coming to an end.  "never do, never do..."
long silence, only radio  WXPN morning show
Adders: What does "fuck" mean?
Me: ah, ahem,  it's just an oath.
Adders: what's that?
Ags: dad, so this is my boo-boo?  points at scratch on her leg. im driving, cant look, but think i get her drift.  She's trying out the  finger quote thing.
ME:  an oath.  a curse.  something you say when you're angry. An exclamation.  yeah, but, so, Ags, in that case you'd say, you wouldn't say "boo-boo" because it IS a boo-boo.  You'd say it's a "laceration"or a "giant cut" or "a sucking chest wound"  That's your "sucking chest wound"
Rearview: Ags all smiles, so pleased.  Adders and Wyatt, chewing on what "fuck" means.  I might get out of this yet.
Me: it's just a really powerful expression of surprise or disgust or anger or whatever.  You dont hear it a lot in polite company.  It's for when you're, I don't know, the conditions have to be just right.  I never say it in front of Birdie or GG. [grandmothers, not technically true, but for the age. . . ]  It would be rude and  inappropriate.
Wyatt: you say it to Nate.  I've heard you.  A lot.  laughing
Me: yeah and Lex and Scott.  It's a good word.  A lot of times.  other times it's a terrible word.  Make sense?
Rearview:  yeah. okay. sure.
Me: Adders?
Adders: uh-huh.
Wyatt:  Nadielis [a neighbor girl] says it a lot.
Me: I don't think she understands the rules for it.
Ags: Nooooo!
Me: it's a bad word.  Sometimes.
long pause.
Wyatt:  Wait.  No.  Dad!  Its a "bad" word.  finger-quote thing.
Me:   three backward fist bumps.