The thing is… Since the first year in Hogwarts, Sirius is a Christmassy person. A very Christmassy person, thank you very much. And a very annoying person, too.
It's a talent, he's a natural, Remus muses. Only a natural born annoying person could manage to drive so many people insane in such tiny frame of time.
It doesn't matter if you like Christmas or if you are Scrooge, if you are around Sirius in this time of the year, you'll start hating it!
He sings "A Cauldron Full of Hot, Strong Love" (non-stop, at the top of his lungs), he strolls around with mistletoe, hanging it above everyone's head (leading to a very embarrassed Peter and a very mad Lily… you can picture what happened), he wears Christmas' sweaters (and other themed clothing items), he decorates and he bakes and he shops…
Lily tried to quiet things down a bit and show him some muggle movies… Let's just say… This lead to a "Home Alone" marathon (three times… in a week…) and the "Lassie" one? Don't mention it around Sirius… EVER!
Remus loves him. He truly loves him. And he's a very patient man. And he thinks that this joyful spirit is kind of adorable… for the first couple of days…
Right now, he is ready to shove the Christmas tree up in Sirius' ass!
It's cold! And raining! And they have been shopping for hours! They have less than 10 people in their list, but they are strolling up and down Diagonal Alley for hours and hours… He's exhausted, wet and freezing.
"Padfoot, come on… Let's go home, please…"
"I have to buy Lily's gift and then we can go…"
"You are looking for a gift for the last 3 hours! Just buy her a scarf or something and let's go home! I'm freezing!"
"I'm not giving a scarf to her! It's boring!" Sirius sounds outraged.
"So, give her fireworks, for Merlin's sake!"
"Fireworks?"
"It's not boring, right? Especially, if you light them right before you give her the gift…"
"Moony! Stop it! You are not helping!" Oh good, now he's whining and pouting like a 5-year-old… This is going to be a long day…
"Sirius, don't pout. And don't whine. Stop being a picky brat. Buy her something and let's go home before you catch a cold…"
The other man comes closer and whispers. "So, you are concerned with me, Moony? So, so sweet of you!"
"No, I just don't want to deal with you with a cold. You are insufferable when you get sick…" Remus smirks and takes a step away for him. "And you smell like a wet dog! Stay away!"
"You are hurting my feelings!" He huffs and crosses his arms. "I'm trying to please everyone and you are a party spoiler!"
"Sirius Orion Black! Stop with the tantrums and move faster! You have 15 minutes to pick the rest of the presents or you'll do it alone!"
"There a lot of things I can do in 15 minutes… None of them related with shopping…" Sirius smirk is more than suggestive…
"Sirius… I'm warning you… Tik-Tok…" Remus growls.
"If I take my sweet time… What will you do, Rem?"
"Put you in the dog house! Move on!"
Sirius pout is substituted by a huge grin. The werewolf cringes at the sight. He knows that grin. It's the "I have a brilliant, dangerous and possible illegal idea" grin…
"LOOK! That's perfect!" He points at a little shop across the street. "Look, Moony isn't it the best gift ever?"
Remus is confused… To say the least… He's over excited boyfriend is dragging him to a… Pet shop? "Pads… What are you doing?"
"Look! She'll love it!" Sirius is picking up a tiny kitten from an adoption box.
"A CAT?" The taller man exclaims. "You want to give her a cat? It's like your natural nemesis and you'll give one to Lily?"
"Why not? She's a cat person… And this one is kind of cute…"
Remus supresses the urge to check if he's running a fever… Sirius must be delusional, it's the only explanation… He has nothing against cats, but that one is just… ugly. It's an oversized, ginger tabby kitten, with dishevelled fur, huge orange eyes and squashed nose. His legs look arched and his tail is a fluffy mess of hair…
"He's just… so ugly, Siri…"
"Shush! Don't say that! You'll hurt his feelings! He's cute! And he has a smart-looking face… I'll take him! She'll love him… He has Prongs' messy mop and almost Lily's hair colour! He's perfect"
The other man sighs… There is nothing he can do and Sirius really followed his request, he picked a gift in less than 15 minutes… It's just a weird gift… With such a piercing stare… He looks kind of smart, actually… Maybe he's not such a bad idea after all… At least, it's legal to adopt a cat…