In the Sex Education / Drugs lesson in year 9 once, we were talking about pregnancy. Some teen sex expert came in and gave us a chance to put anonymous questions on little notes and into a box so that if anyone had anything they were too nervous to bring up around their friends, they could ask in confidence.
The first one he read out was something like "How long does it take to realise you're pregnant?", and the second something about adoption etc. When he picked the third up, his face dropped and he said "I thought this might happen: 'What is the recipe for lentil soup?'."
Next one: "Does Darth Vader have a penis?"
"Winky wanky woo."
"How come nipples are ticklish?"
By this point, the boys were all engulfed in laughter and so the guy just quit and we did wordsearches. What a day.