This week: a supply teacher in London
I remember one of the reasons I joined the armed forces: to stand tall and be able to hold my own in an argument, a fight even - something I could never do at school. But it didn't work. Holding a gun doesn't give you authority because at five o'clock you have to give it back.
A career change later and I'm thrown into a south London school by my supply agency. They have promised it is a reasonable comprehensive with a headteacher praised for its progress.
I arrive at the half-empty staffroom and am given a list of classes, but no briefing. Then I realise my first lesson is Year 9 PSHE. There is no plan, no programme, no list of names, and I've been lumped with the hell-on-earth teaching assignment: sex education. Suddenly, rejoining the military seems tempting.
It's going to be a free-for-all, so I decide to see how far I can get by just being engaging. As I turn the door handle and walk in to the cosily carpeted room, I feel like I'm doing a freefall base jump.
Immediately, I spot the pupil who is going to be trouble - a boy with combed-down hair who is surrounded by a giggling entourage. Straight away, he asks one of the standard questions posed to middle-aged male teachers: "You got kids then?"
"Nope." Here we go.
"A wife?" (Do I feel a lesson on homophobia coming up?)
"Is that really relevant?"
"Tell me you've at least got a girlfriend." The fans laugh out loud.
"Have you got a girlfriend?" I ask, hoping he won't notice my ploy.
"Oh man - I got many." More giggling from his fans.
"And do you use a condom?"
"Oh fuck dat!" He's fallen for the trap. One of his group has stopped giggling.
"'Really? So what happens when you get someone pregnant?"
"I don't care - it's all about the punani!"
"So you've never heard of ... the CSA?"
The tactic of using initials to suggest a Bond-like secret society normally gains a few seconds.
"Child Support Agency - they'll be knocking on your door to collect the money for any child you father. They'll find you, and on average it'll cost you #163;60,000 to bring up a child. Some guys will pay over half of what they earn, practically leaving them destitute."
"Which brings us to today's lesson - birth control." I breathe out - I know where it's going from here.
Sometimes a plan isn't necessary. And I feel 10-feet taller than when I was in the forces.
Tell us what terrifies you, or share the unscripted events from your classroom, and you could be paid #163;150. Email firstname.lastname@example.org.