My mom told me she tried LSD in college and sat at the end of a driveway playing in sand. Also, when she told my brother and me (but not our younger siblings at the time) about the birds and the bees, she told us, "so your father and I had to do it FOUR TIMES." < dramatic chipmunk >
I think I walked in on them a year or two later, but it was dark. There was some climbing around - forward cowgirl, maybe - but nothing graphic. I quickly walked out without further investigation.