Compound Nouns

I was trying to teach Year 7 about compound nouns. In French you can't make compound nouns in the same way as it is possible in English. Cheesecake becomes Gâteau au fromage, for example. Other compound nouns are formed with a partitive 'de' like pomme de terre for 'earthapple', or potato.

Me: So for example, you might stick two words together in English to make a new one. Hourglass, for instance. Or steamboat or Hogwarts or laptop. Can anyone think of any other compound nouns in English?

MM: Dickhead?

DJ: Bumhole!

KB: Dumbarse!

Well at least they understood the grammatical principle.