The fog clears and here we are.

It’s Year 4 and the theme this half-term is a hangover from 2012: the Olympics. The children have been doing the Olympics and when I ask them what they know, they know loads. We are all proud to remember our list of Olympic values: determination, equality, inspiration, courage, friendship, excellence and respect. Sammy, who arrives late, having forgotten to put his uniform on this morning, is able to recite these attributes straight off, no worries. Sammy beams.

Josh is sitting at the front. He’s the sort of child who gets overexcited very quickly and has that knack of finishing your sentences ("under his breath") under his breath. It’s a weird skill, and I’ve met people like him before. I need to try to stay one step ahead.

Josh is sitting next to another boy who has a fixed grin not dissimilar to that of a fox who’s just discovered an unguarded chicken coup. I’m scared to ask his name in case his face cracks.

The teacher has asked me to introduce the idea of cheating as a kind of anti-value, using a narrative to get the class hooked.

I mime getting on a bicycle and ask them what Olympic sport they think I’m taking part in.

"Motor racing."

"Cricket."

"Running fast."

The teacher raises her eyebrows, as I raise my game and repeat the mime.

"Cycling!" exclaims Josh before I’ve settled onto my imaginary leather saddle.

Spot on! I then segue into a teacher-in-role commentary on how disappointed I am to lose another race. The children and I decide that this disappointed racer is called Jake.

"Like Josh!" shouts Josh.

I nod, confused, but letting it ride.

Thinking of the Olympic values, I ask what we could say to encourage Jake the Olympic cyclist. Which words?

The children talk and then contribute a series of thoughtful and motivational comments, the type you find laminated in school halls around the world.

"Wow, yes, I need to be more positive," I say, speaking as Jake, "I just need to believe in myself more and embrace my potential…"

“Chill yer beans!” shouts Josh, breaking Jake’s spoken thoughts.

“You what?” I ask, in a rather unteacherlike fashion.

“Chill yer beans!” he repeats, with Fox-Grin sitting next to him, almost exploding with glee.

“Get up, come and stand opposite me,” I instruct Josh, and he does so immediately. In my head, I’m inventing a new behaviour-management strategy called DfB (Drama for Behaviour). I’ll be quids in.

I tell Josh to hold out his hand to me as if he’s offering me something…a vial of liquid, and he immediately shouts:

"It’s body-swap juice!!"

He’s not far off the mark, to be fair, but I need to keep control of the narrative, as I am the teacher.

"Okay," I scramble, "swap places with me, Josh, and you be Jake, and I’ll be you."

It’s a simple swap-over at the front of the class and they have no problem keeping up.

And now I am Josh, excitable Josh, at the heart of the story. I say the following:

In my fingertips I hold the glass vial that contains the liquid that will make Jake become the best cyclist ever. Take it, Jake. Take it. Drink it.

Josh takes it and mimes drinking it. Before he can go into Jekyll/Hyde convulsions in front of the observing teacher colleagues and class, I motion for him to sit down and, fair play to him, he does, eyes never off me.

In an attempt to avoid confusion, I say to the class that we can change the name of the shady character offering Jake the vial, from Josh to John.

"That’s my middle name!!!!" shrieks Josh and my eyeballs widen. It’s now going at 90 miles an hour in my head.

"Okay," I proclaim, as the class laugh at Josh’s excitement. "Let’s call him JJ!"

At that point, it’s like the walls are going to cave in. The class can’t believe it.

Fox-Grin stands up, his grin widens to that of a suspension bridge.

All the class are pointing at him. I’m confused (again) and the teachers are laughing into their clipboards.

In a weird Spartacus moment, Fox-Grin shouts:

"I AM JJ!!!"

They all think I’m a chuffing mind reader.

JJ (for that is he) falls to his chair in hilarious disbelief that this strange man in a Matalan suit would actually know his name. He and Josh high-five.

We eventually namecheck Lance Armstrong, but don’t dwell on it.

And the fog descends.

I’m laughing about it as I write. Josh, JJ and Sammy can push anyone to the edge of human endurance. Teaching, it appears to me, is a human value. It also takes genuine agility.

Hywel Roberts is a travelling teacher and curriculum imaginer. He tweets as @hywel_roberts. Read his back catalogue and follow him on Facebook