The awkward questions have started already.
How does Father Christmas get round the whole world in just one night without stopping for something to eat? How does he know what everyone wants? And how come those felt tips in my stocking last year came from Tesco?
The minefield of keeping the magic alive becomes trickier to navigate every year. But isn't it the case that when your back's against the wall, you come up with your best work?
So there I was trying to think on my feet, desperate to limit the length of the pause which one day will expose the lies, and I came up with Mother Christmas.
She's the unspoken heroine who fixes all the stuff that little minds deduce the old, fat guy with a beard is incapable of. She's the one who packs the sandwiches, she compiles the lists of what every child has asked for and she shops at Tesco online.
Not only did my six-year-old son accept my explanation, I heard him selling it on to a friend in confident 'haven't you heard of Mother Christmas?' tones.
Phew, I got away with it was my first thought. But then when I started to think about it, I wondered why the hell not!
Aren't we, the women, the ones who make Christmas happen? I have yet to have a conversation with a dad about stocking fillers, let me tell you. Trudging the aisles, scanning the shelves and looking online for bits and pieces which reflect your kids' interests is mostly women's work - and can you believe a man gets all the credit?
Why shouldn't we have a part in the legend?
I'm not suggesting we change the storyline that dramatically - even though it would be satisfying to have a female festive boss.
Simply that Mother Christmas would make the picture more representative of the real world. Heck, it might even make it more believable. In my experience, when children want something doing, they go to mum, because she can make things happen. Dad is generally too busy checking the scores on his smart phone to hear the first 18 requests for a drink and a biscuit.
Just imagine, Mother Christmas in a dashing red faux fur-trimmed boiler suit, legging it up and down the toy shop aisles. It's not too far-fetched a picture is it?
And think of the benefits on Christmas Eve.
Along with leaving a carrot for Rudolph and a mince pie for Santa, we could suggest the kids leave a bottle of wine for him to take back to his wife...
5 Things You Never Knew About Mother Christmas
1. Father Christmas won't ask for directions because he's a man. So Mother Christmas makes sure he doesn't get lost by planning his route on her Santa Nav device. On Christmas Eve, she monitors his journey via satellite and speaks to him about time management using a call centre-style head mic.
2. If your kids worry that the Father Christmas at the local grotto looked confused when they asked for a 4DS Leappad Ninjago Nunchuk, reassure them Mother Christmas will know what they meant because she a) has a Santa Cam hidden in his beard and b) knows everything.
3. Sometimes price labels get left on stocking presents - this is because Mother Christmas wants to teach children about the value of money and not because she forgot.
4. You never get to see Mother Christmas because by day she is in charge of the elves at Lapland HQ, where she oversees the buying and wrapping departments. By night, she pops into Toys R Us by prior agreement with the store manager.
5. Mother Christmas is not as fat as Father Christmas because she rushes around a lot more than him.