I would add that the comment about "freak dancing" is right (although not everyone does it - there's also a lot of dancing in groups with friends, too), but in my experience, teenagers don't really call it that.
Want to make a room of teenagers laugh? Put an uncomfortable-sounding school administrator on the PA system to announce that, at the upcoming homecoming dance, there will be a ban on - ah, erm, ahem - Freak Dancing. (said in most awkward, stilted way possible.)