this is tooooo funny. savage did a column for The Onion about adults' misperceptions about sex when they were kids.

one (milder) example:
When I was in the sixth grade, our friend Tom, who lived on a farm and thus had instant credibility in our group concerning all things reproductive, told us that when we were older we would have to have sex, but as males we would get no satisfaction from it. When asked to explain, he replied, "When your ear itches and you scratch it with your finger, what feels better, the ear or the finger?" Made Sense Then

http://www.theonionavclub.com/savagelove/index.php?issue=4034 

Unfortunately once you get married the "ear" never itches.