Well my husband and I were having a bit of early morning fun, when we heard a knock at the (locked!) door.... it was our oldest daughter (who's 8) and here is how the conversations went....

Dad: Yes?
Child: What are you doing?
Dad: Listening to the radio. (Which YES the radio was on!)
Child: nuh huh... is mom ok?
Dad: Yes, mom is fine.
Child: Are you sure she didn't sound fine.
Dad: Yes, I'm positive she's fine, ohhhhh look at that early morning hair! (yep, time for distraction)
Child: DDDAAAAAAAAAAAADDDDDDDDD!!!!!!!!! *trying to peek around the door* Are you sure mom is fine?
Dad: YES! Mom is fine... although she would have been better if you had slept a bit later!
Child: HUH?
Dad: *stepping back out of the door* Go snuggle....

Mom: Who is that?
Dad: It's the oldest.
Mom: Comemer'
Child: Mom, what were you doing? (of course she asks me and NOT Dad!)
Mom: Talking to Dad.
Child: Didn't sound like talking... *skeptical frown at mom*
Mom: Trust me... it was good talking.... OHHHHHHHHH look AT that early morning hair! (Yep, my turn now!)
Child: MMMMOOOOOOOOMMMMMMMMMM! So, when are ya gonna tell me what you were REALLY doing?
Mom: Ummmmmmmmm.... probably never.... are you eating at school today or packing? (Yep, second distraction)

45 minutes later...

Child to younger sibling: Mom was ok this morning but BOY was she loud. *Giving mom and dad the "evil" daughter eye.*
Younger Child: Why was she loud?
Older Child: She was talking to Dad.... but I don't think it was talking.
Younger Child: Momma what were you and Daddy talking about this morning....
Mom: Better hurry the bus won't be here soon enough!

So... when do you actually explain the "birds and the bees" to the kids? Personally I was planning on waiting at least 4 more years for the oldest 2... but now, I'm not so sure... (As I silently pray that neither of them ask their teachers about it... lol)