It's January, still dark on your journey to school, and those sad bits of Christmas streamer dangling in the corners of the classroom aren't helping your mood. You - and your pupils - need cheering up. You need a good laugh.
And that means something a bit more substantial than recycled jokes from the Christmas crackers.
Children always have stories to tell. So if yours are a chatty bunch, it might just be a case of picking a few seasonal topics - "The day we went to the sales" or "Trying to get ice off the car" - then asking for volunteers to stand up and tell a story. The class characters will start things off, and if you laugh and nod in the right places, others will soon follow.
Bolstered by remembered repartee ("My dad said it would fit Godzilla,") and a bit of luck, you'll feel the mood lighten and may even enjoy some examples of the kind of lugubrious humour at which many children excel.
Laughter is good for you and for children. You won't find it on the national curriculum or in any government initiative, and yet as Peter Wright, recently retired head of Hazel Oak, a special school in Solihull, insists, it is a vital ingredient in the classroom. "Children come to us with all sorts of issues," he says. "Many come from mainstream, stressed and feeling down. Humour can lift them; I use it to defuse confrontation, to show children another way to react, and to set up friendship bonds."
Mr Wright encourages children to laugh at him; in assembly he will pretend to trip or "accidentally" blow his nose on his tie. (When he won the lifetime achievement prize at last year's Teaching Awards he took to the stage like a natural. "You've just made an old man very happy - haven't they, Melvyn?" he said, flashing a glance at Melvyn Bragg, who had just presented the shiny Plato and who duly laughed his head off.) Hazel Oak school, which Mr Wright has helped to save from closure at least twice, places great emphasis on preparing children for social interaction in the outside world. "They don't wear badges saying they have learning difficulties, so their lack of social skills can give them even more problems than the academic side. An autistic boy said to me, 'Your jokes help to me to understand what your world is about'.
"I can be genuinely stern, or I can look stern as part of my humour.
Children learn to understand the difference from the context and the way you set things up."
Younger children will always respond to silliness. For example, a staple of the humorous teacher's repertoire is to read the register as usual, but to insert daft or fictitious names - "Willie Wonka", "Kylie Minogue" - and then look innocently around for a reply. Or to say things like, "How old are you? Eight? I was eight when I was your age."
It's a very child-centred brand of humour, as is my own invention, the "body band"; this involves putting together a musical group of infants who can produce a range of tongue clicks, cheek slaps, whistles and underarm raspberries. Children know that this kind of thing is entirely for them, and understand - maybe only half-consciously - that in deploying it, their teacher is showing them affection and understanding.
It is for this reason that a jokey approach can help a child who has a problem they find difficult to talk about. "It makes you seem approachable," says Peter Wright, for whom familiarity is important.
"Children have favourite stories, they recognise your style and can see what's coming." For 26 years at Hazel Oak he's been telling stories about himself, his family and pets. "I've told them often about when I was a small child and went into the larder and ate all the filling from a dozen mince pies. When my mother handed them round they were all empty." His pupils like the story so much they dramatised it for his retirement concert last month.
Further up the age range, the Year 9 teacher who winds up a tutor group about a football match ("Remind me, what was that score again, Darren?") is doing much the same thing: giving a signal of friendship. Done properly, it's not an embarrassing attempt to curry favour, or get down to the pupils' level; a good teacher can do it without losing authority. It's behaviour David Attenborough would enjoy describing were it exhibited by apes in the rainforest.
Humour seems to work best when it emerges from an apparently stern or serious background; in Coventry people remember an authoritarian teacher of pure mathematics who would frown and "chalk" the end of his pointer with snooker chalk when he made an error at the blackboard. And I remember my headmaster taking an A-level economics class and suddenly turning on me and saying, "What does a holding company make, Haigh? Cheese?" The absurdity of that august and feared man dragging this concept from nowhere makes me laugh out loud even now. And, importantly, I remember still that a holding company makes nothing.
Humour is all about engagement. Good teachers have positive relationships with their pupils, and a well-timed jokey remark can help with this bonding process. It can show just enough of a chink in a teacher's armour to reveal the human being underneath. As Peter Wright says: "It's important for the children to see me get things wrong. We laugh together. I do that to help them see that it's not making mistakes that matters, it's what you do next.
They see that laughter doesn't make the situation less serious, but it does take the tension off."
It's not always that easy, of course. If you set out to make children laugh, you have to know what you're doing. "The danger is that what they remember from the lesson is the humour and not the content," says psychiatrist Raj Persaud. "The difficult art is to embed the humour in the material."
It's also important to stay in charge. "You're funny for a while, and then comes the point where you have to exert control," adds Dr Persaud. "If you're not careful the class can take over. Adults can manage their moods, and be aware of when it's time to be serious. Children have difficulty with that."
It's a scenario every teacher will recognise: pleasure that the humour's working, then panic as the laughter spins out of control and children start shouting. You may react by retreating into authoritarian mode, angrily telling them to shut up. Then comes the hurt reaction, and the knowledge that your relationship with the class has taken two steps back. One head I know had to tackle post-staff pantomime hysteria while still dragged up as the Dame. "I took the wig off," he says. "That seemed to help."
Gerald Haigh is former head of a middle school in the West Midlands