Primary teachers are a pretty tame lot. Reliable, sensible, upstanding members of society. We don’t swear or chew gum; we wear sensible shoes and a warm smile. We’re everything the outside world would want us to be.

While our secondary counterparts are free to enjoy crazy hairstyles, sarcastic banter with the kids and passionate encounters in stock cupboards (I’ve seen the sitcoms - everyone knows secondary staffrooms are a hotbed of sexual tension), we are conservative, restrained and spend our breaktimes conducting recorders and reminding five-year-olds how to use a knife and fork.

All very polite and sedate.

The majority of those not working in primary schools must, therefore, presume that a primary Christmas staff party would be a pretty gentle affair. A nice meal in a well-lit restaurant, a couple of glasses of wine, a gentle discussion about Strictly Come Dancing and then home by 10.30pm.

They would be wrong. And there are plenty of signs that all would not be quite as sedate as an outsider might imagine.

In the world of the primary school, Christmas spirit arrives early. After a good three weeks of tinsel, carols and mounting excitement, you would have to be the most hardened of Scrooges not to feel a warm glow of festive cheer. We don’t get as excited as the children, but that Christmas jumper we scorned at the start of the month becomes essential wear and the Rudolph ears we threatened to bin are on our heads from the moment we leave the house.

It’s the ideal time to be as childish and irresponsible as we can manage

We’ve had plenty of practice parties, too. This is the season for constant school social engagements of varying degrees of formality, most notably the all-encompassing nativity. So when we finally get to put the donkey and angel costumes back into storage, the chance to party in a manner that doesn’t involve pouring orange squash into 30 cups is as welcome as a king in a stable.

And then there’s the mindset (of the non-Carol Dweck variety). Teaching is a great job, but after a term of it most teachers feel like they’ve been put through the wringer. When Christmas finally arrives, our energy levels have plummeted to the point where struggling into some going-out attire and leaving the house seems like a Herculean task.

But that first drink in the company of colleagues is unrivalled in its revitalising properties. We don’t get to talk to each other enough. Teaching can be an isolating job. We spend most of our working hours marooned in separate rooms, lost in a sea of children, so a quick five-minute chat in the staffroom - before we are called away to console a child with a grazed knee or to do battle with the photocopier - is often the best we can hope for. Therefore, the opportunity to congregate in a child-free zone and be given free rein to socialise with people whom you see every day but don’t often get to chat to is irresistible and intoxicating.

And so we embark on the festive celebrations. We are easy to spot. In some restaurant or bar, or staggering down a local pavement, you’ll see a group of people who could only be a primary school staff Christmas party.

It will be a large female crowd of mixed ages, interspersed with the occasional male. There will be lots of noise, laughter and red wine. And, probably because we spend our days modelling how to be sensible and mature, you’ll see a lot of interesting behaviour: the Christmas party seems the ideal time to be as childish and irresponsible as we can manage.

If you are a primary teacher and you don’t do this, you should be doing this. We deserve it. So here’s my Christmas party guide for primary teachers:

1 It’s all in the timing

The timing of the Christmas party is vital. It has to be the very last day of term; anything else is just asking for trouble. But this is particularly tricky when you break up for Christmas on a Tuesday or Wednesday. If you have the party on the Friday before, then a weekend is nowhere near long enough to eradicate the memories of what went on. No one wants to face their headteacher or key stage leader a mere 48 hours after having loudly criticised their marking policy while dancing on a table and spilling red wine on them.

An entire Christmas holiday is the only safe amount of time to ensure that the memories fade. Any lingering recollections of pre-Christmas indiscretions will dissolve in the fog of misery that hangs over the return to school in January.

A weekend is nowhere near long enough to eradicate memories of what went on

Don’t even contemplate having the staff Christmas do on a school night. I’ve only done this once (on a Thursday night after no one remembered to ring the restaurants and all the Fridays were booked up). It was a mistake. Having finally made it home by 4am, going out to greet my overexcited class on the playground less than five hours later was one of the more painful mornings in living memory.

One of my fellow teachers, for whom the evening had doubled up as a leaving do, was so “overcome” by the situation during morning assembly that she only managed to get a few words into her leaving speech before she had to flee the hall, clutching her flowers and cards.

She spent the next few hours lying on the floor in her stock cupboard while her class enjoyed their end-of-term games day and her trusty teaching assistant guarded the door.

2 The venue

Choosing the right venue is very important. Too close to school and you run the risk of bumping into parents; too far away and you may not remember how to get home. Of course, one sure-fire way to avoid bumping into parents is to have the party in the school itself. Instead of gulping down a lukewarm cup of tea in the staffroom, you can sit back, relax and play Pictionary on the message board while leaving beer stains on the carpet and scattering crumbs on the health-and-safety box files.

One advantage that a staffroom has over a restaurant is added facilities. As the evening wears on, it’s not unusual for someone to suggest adjourning to the hall and getting the PE equipment out.

However tired and drained the autumn term may have left you, there is little in life more therapeutic than polishing up your Tarzan impression on the gym ropes and cheering on the deputy head and caretaker in the final of an obstacle-course competition created in direct defiance of the school’s health-and-safety policy.

3 Staying professional

Even off-duty, we are still professionals to the core and a Christmas party is no reason to miss a learning opportunity. Practical maths should feature at the staff Christmas do. How many teachers can you fit in a phone box? How many members of staff can balance on a picnic table without it collapsing? What is the best angle to position an After Eight on your forehead so you can eat it without using your hands?

Determined attempts have been made to answer all of these questions, and many others. My particular favourite of these learning opportunities was the time that we decided to investigate balance and friction by playing “Human Buckaroo” with a sleeping teaching assistant (we were up to about 20 items until a poorly positioned staple gun proved to be a tipping point).

4 The NQT trap

Newly qualified teachers can be something of a concern at the staff Christmas do, as safely navigating your first Christmas party as an NQT is a delicate business. For a young teacher, fresh from their student days, a big night out is a regular occurrence and something that they feel falls well within their skillset.

But a staff party is a very different beast from the egalitarian student free-for-all and, since an NQT who has survived their first term in teaching will have more reason than most to hit the party hard, it can be all too easy for them to slip back into student party mode, forgetting the lines of professional hierarchy that subtly underpin even the most raucous of nights out.

One NQT lifted the headteacher up in the air and tried to wear her as a hat

As a more experienced member of staff, it is your duty to help the NQT to steer a safe course, but if this fails then the only thing to be done is to sit back and watch the entertainment. Over the years, I’ve seen many NQTs cross the line in spectacularly entertaining fashion (including the time one lifted the headteacher up in the air and tried to wear her as a hat). Luckily, they have all lived to teach another day.

5 The final leg

Like the majority of festive celebrations, every school Christmas party has its die-harders - a small but stoical faction who will keep going long after others have departed. In my advancing age, I am trying, for the sake of my health, to detach myself from this group, having spent years starting the night with pacts to share a taxi home before the queue builds up at 11 only to find myself conga-ing through the town centre at midnight en route to some awful nightclub. I’d like to be able to tell you what goes on at the hardcore end of the staff Christmas do but the honest truth is I really can’t remember.

Jo Brighouse is a primary school teacher in the Midlands and a TES columnist