In schools up and down Wales this week, the timetable is being jiggled around to prepare for that all-important Christmas play or concert. And that means lots of rehearsals. So maths is moved, which shifts literacy, which knocks on to music, which means PE is cancelled. A shorter playtime here, a longer lunch there - all semblance of routine disappearing in a confusing mist of uncertainty and last-minute changes.
If you are one of the many children in Wales with Asperger's syndrome or autistic spectrum disorder, for whom routine and order is more important than Santa himself, you may think this term was invented specifically as a festive torture just for you.
It starts innocently enough in September, with a different classroom, a new set of routines and, most daunting of all, a new class teacher to get used to. You had only just worked out that, when the old one's face went really red and wrinkly and her eyes looked like they were about to explode, she wasn't very happy. Now you have to work it all out again.
The schoolwork is getting harder, the homework is gathering pace. It is all a bit difficult, but you are just about settling in, and you have even been Star of the Day once. As half-term arrives, you are ready for a break but you are getting used to things and thinking it is going to be fine.
But then, as November begins and the clocks go back, normality ends. The big build-up to the Christmas performance has begun. The old routine is the first casualty, as the school day morphs around the never-ending singing practices and pupils' bottoms seemingly become welded to the hall floor for hours at a time.
Then there are the rehearsals, with complicated instructions and stressed teachers, who do not welcome children not "getting on with it". There are costumes to try on, with difficult buttons.
And woe betide any mistakes, leading to another evening spent consoling my son - even though it is only a one-line bit-part (at least he got a part).
This time he misunderstood something, and his teacher apparently bawled at him, twice: "You stupid boy."
He's not stupid, he's got Asperger's and a statement. But there is no time for all that "special needs" fuss and bother when you are putting on a concert.
Finally it is all over; the performance is faultless, the encores are flowing. But my son is already worrying about the panto trip, the Christmas party and - worst of all - toy day. Roll on uneventful January.
The author is the mother of a 10-year-old son with Asperger's syndrome, a form of high-functioning autism, at a South Wales mainstream primary school