When I was in highschool, some friends of mine learned German, and they carefully looked up in the dictionary how to be abusive in German. They used to say to each other (and anyone else who wouldn't slap them) "du bist eine runzel hahn" -- meaning "you are a wrinkled cock".
Once I was in University my family had a Swiss exchange student come and stay, and somehow this came up with her. She at first looked puzzled, and then said "why did they find it so offensive to call each other wrinkled rooster?"
A childhood belief about swearing

others believed things like this
- I used to believe if you stayed in water too long your skin would get really wrinkled and stay that way.Anon
- Whenever my fingers wrinkled from staying in the pool too long, I thought I was aging faster.— The Mortal Elf
- When people would ask me what was my background, I would tell them 1/2 German and 1/2 Brooklyn!— Randy
- I used to think it was illegal to speak German in Germany because of World War Two.— Anonymous
- I was afraid of my grandma because i thought she had germs because she was german!Anon
- Since Germans speak German, I thought Jewish people spoke Jewish.— Lori