lol by 3rd grade it'll get giggle but they won't fully know why.
   By 4th grade, they'll know the kind of naughty they *suspect*
   but don't wanna know more about. By 5th grade, they'll *know* -
   the girls certainly (girls always seem to know just a little
   more than boys), 6th the latest for boys. I'd say "Youtube
   generation" but naw, I remember elementary school well; with
   nieces/nephews through th...e years, the type of jokes they make
   and questions asked, I don't think the timeline has changed much
   at all from when I was growing up in Jersey."