I am aware that this is part of a wider phenomenon. Even in affluent parts of the country, the current fashion is for speaking in a Jamaican accent and wearing your trousers pulled down as far as possible. Year 6 boys in many schools waddle around like giant emaciated penguins wearing filled nappies. I wonder if in downtown Kingston, heads despair at their pupils wandering around in expensive ski jackets, braying: "My mummy shops at Waitrose."
The movement of street slang around the country is fascinating. For some years I worked in a school in a "challenging" area. Parents were not much interested in learning but were a great help in basic phonics as many children had their initials shaved into the back of their heads. It was a classy area: children were forbidden to have their navels pierced until they had their own kids - on average at 13. The word du jour was "dark".
For example, when Mr Walpole finally cracked and put the desk and chair of his most irritating pupil outside in the playground for the afternoon, that was considered by fellow pupils to be "well dark" (especially when it began to rain on this poor unfortunate).
When I moved on to a school with a nicer postcode, "dark" was big with the coolest pupils some six months after my arrival. Somewhere in a forgotten town in Cornwall, there is a teacher reading this whose pupils have finally caught up with this "new" expression. They're probably also excited about the first showing of Raiders of the Lost Ark at their local cinema this weekend.
But is any of this new? I myself spent three months trying and failing to master the wrist-flick back in 1983. My week continued in surreal retro vein when, during numeracy, I confiscated a Rubik's cube from a pupil.
While introducing the lesson, I managed to complete three sides, much to the class's amazement. But I'm sorry to say it all went to my head. I was down with the kids. During break, I hitched my trousers down, gangsta-style, so you could see the waistband on my boxer shorts ("MS Comfy Fit"). I took a paperclip from my assessment file and began chewing it. As the class filed back in for literacy, I held my phone in a nonchalant way that suggested I might be about to text another "playa".
My phone! That was my mistake. The sniggering started: "Is that a phone, sir? Has it got video? Is it from medieval times, sir? Do you have to wind it up?" Busted. The class regarded me with a look of patronising sympathy.
Once a dork, always a dork. Maybe that's why I became a teacher.
More from Henry in a fortnight