You are in close proximity with your boss with free alcohol fuelling your decisions - and your dance floor technique.
So, if you DON'T want to behave in a way that leaves you unable to ever show your face in the office again then follow Closer's Andrew Hartley's tips.
He's survived enough Closer Christmas bashes to witness where things can - and often do - go tragically wrong.
Follow his foolproof guide.
Rule number 1
Find the most sensible, boring, OCD, teetotal, party pooper in the office.
Make their humdrum life more interesting by appointing them your official guardian.
Their job; to watch over you from afar. When you start making out with a clearly terrified 17-year-old postroom boy on a pile of coats in the corridor – their job is to escort you to the exit and into a taxi.
Rule number 2
The Christmas party is a good time for a spot of brown-nosing with the boss.
But do this EARLY. As in before you start mixing sambuca into your wine to make "pretty colours".
Remember, good smalltalk with the boss starts like this: 'So, it's been a great year for the business – you must feel so proud'.
Bad smalltalk starts like this: 'Yeh, Christmas is like, soooo bloody expensive – what happened to that rise you promised?'
Rule number 3
It's a fact of life that you will fall heavily to the ground like a baby giraffe on ice at some point during the evening.
Consider wearing arm and knee pads underneath your outfit. (Bonus point: The knee pads will prevent carpet burns if you get lucky with the office romeo…woof!)
Rule number 4
Karaoke.
In Japanese it literally means 'empty orchestra'. But depending on who's singing it, that could be 'empty the room'.
If you must embarrass yourself, know the easy options. Don't Worry Be Happy by Bobby McFerrin - he virtually talks his way through it. Or anything by Madonna – if she can consistently fail to hit those notes, so can anyone!
Rule number 4
Never underestimate how upset people will get during 'Secret Santa'.
And don't think for one minute that they won't launch an investigation into who gave them the (clearly secondhand) packet of feminine wipes and hunt you down. You were supposed to spend a fiver…cheapskate!
Rule number 5
Line your stomach. Yes, that means eating something.
And yes, it needs to have carbs, otherwise one glass of wine will have you gurning like Kerry Katona on This Morning.
Remember, getting into your Christmas party LBD was the reason you've not eaten anything since October. That's all history now – so, KFC party bucket anyone?
Rule number 6
Sex. There, said it.
Secretly everyone in the room is thinking the same thing. "We're all out of our tiny minds on cheap plonk so surely no-one will notice if I slip off to the loos with that guy from accounts?"
YES THEY WILL. Your shenanigans will be all over Twitter and Facebook the next day. Unless you want the kind of reputation associated with minor league WAGs – keep your knickers on!