Been thinking about this for a while, and it seems a good topic for discussion.
Swearing is a talent, and you can separate people into those who can't and those who can do it properly. It's not big and it's not clever, obviously, but it's certainly a mark of someone who can use language effectively. I had friends in Germany who spoke impeccable English, but as soon as they swore it became apparent that it wasn't their first language. Usually they went way over the top of what was acceptable due to not appreciating the power of the words they were using.
Which brings me to my recent thoughts. The syllabus we teach to secondary pupils in KS3, 4 and 5 only mentions marginally "Youth Culture" and frequently only in a preachy, over-protective way. Yet looking back on my own inquiries when I went on our German exchange at the age of 13, I wanted, without delay, to know as many ways as possible to offend the grown-ups around us. The idea of asking a teacher for this kind of knowledge would have been horrifying. But still; why aren't we teaching what pupils want to learn?
I've pointed our kids in the direction of the BBC Language Learning site numerous times, and they'd never mentioned or spotted the "cool German" area (why does it have to be "cool"? But that's another thing...) so I showed it them. There are some quite fruity phrases included, verpiss dich, leck mich am Arsch etc (though they left off aber kräftig, shame). I instinctively felt quite nervous, without reason. They, however, enjoyed it. My problem is now how to follow it up without causing offence...