A/N: Kurt doesn't know when it became tradition that Sebastian gets to be the fun dad, but he doesn't necessarily have to like it.
Written for the Hummel Holidays prompt 'traditions'.
Kurt doesn't know when it became a tradition, but the first time it happened, he was determined not to like it – his husband and son falling asleep on the sofa after making an epic, whirlwind mess trimming the Christmas tree. Boxes were left open and scattered around; old ornament hangers stuck up from the rug like dead roots, poking at the bottom of Kurt's foot as he walked, no matter how many times he'd thought he'd gotten them all; and silver strands of tinsel hung off almost everything except the tree. But when the dust of his own irritated grumbling settled and he took a moment to look at his two miscreants, cuddled together, Thomas underneath Sebastian's arm with Sebastian stretched out on the couch, taking up every conceivable inch of space, Kurt had to admit they were adorable.
Honestly, seeing them like that made Kurt kind of jealous. Kurt's the disciplinarian. He lays down the law, and he makes up the bulk of the rules and decides the punishments. Sebastian gets to be the fun dad. He's the one that jumps headlong into piles of leaves without worrying about grass stains or contusions. He's the one who brings home ice-cream cake for dinner just because, or wakes them all up at midnight on a school night to go for a drive through the first falling snow. He's the one who persisted with the idea of getting Thomas a companion animal when Kurt's first three opinions on the subject were no, no, and no. Kurt's one attempt at spontaneity – a Happy Meal picnic in the front yard – was called on account of a freak, unexpected rainstorm. And Sebastian came to the rescue by constructing a make-shift tent for them to sit under so they could watch the downpour while they ate, in opposition to Kurt's suggestion that they eat indoors in case lightning started, and to keep Thomas from catching a cold…which he did.
But it was a great picnic. Thomas still talks about it.
Kurt's insistence on rules and order are the boundaries within which Sebastian feels free to run amuck, and Kurt was afraid that he might start resenting Sebastian for it…until Kurt realized that this relationship Sebastian has with their son doesn't take anything away from Kurt. It's simply the way they communicate, thru the complicated linguistics of tickle fights, crude jokes, and laughing till one of them snorts milk out their nose.
This is a language Kurt doesn't know how to speak as well, but his role in the family dynamic has always been clearly defined, since day one.
When Thomas falls down and scrapes his knee, he goes to Kurt.
When his stomach hurts and he feels nauseous, he goes to Kurt.
When he has a nightmare and he can't go back to sleep, he goes to Kurt.
When he needs advice about something in school, or he needs help with his homework, or he's worried about Hepburn, he goes to Kurt.
And that job is as important as always being the fun dad.
In fact, Kurt knows that Sebastian wants just once to be the one Thomas runs to when he has a splinter, or he sprains an ankle, or when someone at school calls him a name.
Kurt and Sebastian sometimes joke that they are the equivalent of a completely in love but divorced married couple – Kurt gets Thomas on the day to day, and Sebastian gets evenings and weekends. But holidays are Sebastian's time to shine. He looks forward to them for months. It's his and Thom's time to bend the rules (with Kurt's permission, even though it also comes with a dose of disapproval), watch cartoon movies until sunrise, spend all day in their pajamas, eat cookie dough out of the roll, wrestle on the front lawn, and all of the other things Kurt normally rallies against.
It's a tradition that Sebastian gets to be the fun dad.
And Kurt will let him keep it.