For Remus' twelfth birthday –the first birthday Sirius knew Remus and coincidentally, Remus' first birthday at Hogwarts- Sirius decided to give Remus a calendar containing several pictures of heavy breasted women in bikinis. Sirius went the extra mile and filled in the spaces every month when Remus' would be away to see his sick mum back home. Sirius did this with no knowledge of Lupin's lycanthropy and filled in the boxes based on Remus' previous absence record. Sirius also did this without knowledge of Remus' blunt and transparent sexual orientation.
For Remus' thirteenth birthday Sirius gave Remus a torch. The torch wasn't important, but the card Sirius had charmed to sing "Welcome to sweet adolescence, here the female population sprout bazoomers and the boys become men!" was a lot more important, funny and entertaining.
When Remus turned fourteen Sirius delivered Remus a bright blue jumper with a warm sun stitched onto the front. This was perhaps the first gift Sirius had given anyone that was useful or deemed a "good" present. Remus commented about how Sirius had managed to remember the comment he had made two months prior to his birthday about Remus' favourite thing being the sun because it meant there wasn't any moon to deal with.
Sirius blushed at this and his secret crush was almost stripped naked for everyone to see, but he stealthily covered this by choking on some yogurt. Nice save.
On the day Remus turned fifteen Sirius turned into a large black shaggy dog for the first time.
However, on the day Remus turned sixteen events turned for the worse.
"Padfoot?" Remus asked nervously, prodding the present –wrapped in a brilliant shade of purple- with his wand. "What is this?"
Sirius bobbed into the dormitory and smiled. "That is my present for you."
"Why did you leave it on the bed?"
"That's your bed. I thought that would be the best spot to leave the gift that is yours. Happy birthday, by the way." Sirius kissed Remus on the cheek and sat on the edge of the four poster next to him. "And I didn't want to give it to you in front of anyone else. Even James and Peter."
"Is it safe to open?" Remus asked cautiously.
"Of course," Sirius scoffed. "why wouldn't it be?"
"It looks… murky."
"Just open it." Sirius said dryly.
Remus tore open the purple packaging very tentatively, almost as if he was trying to disable a bomb.
"A leash and collar?" Remus raised his eyebrow, he was almost amused. "Is this meant to be some sex thing?"
Sirius laughed. "Stop looking so terrified! It's most certainly not a sex thing at all. The sex thing present's coming at Christmas or Valentine's Day, I haven't decided yet. Wait, I've got it. Halloween."
Remus sighed a breath of relief as if a heavy weight had been lifted off his back. It wasn't a sex thing, thank God. "It still begs the question, why have I got this?" He rattled the leather collar and leash in his hand.
"Because you're a werewolf and it would be very amusing for me to drag you around with it about the school."
Remus nodded and let this register. "There is no way in hell I am going to do that."
"Why not!?" Sirius whined, looking disheartened and equally amused.
"Because it's ridiculous!"
"How so?" Pressed Sirius.
"I'm not answering that." Remus said. "I shouldn't need to explain that."
"But it's funny because we'll -with the exclusion of Prongs and Peter- be the only ones that know about it! It's hilarious!"
"Ha ha." Remus reeked of sarcasm. "It's not so funny when you're the one that will have to wear it."
"Yes it is. I'll wear it to proof you wrong. You'll see. And when you do see the fault in your ways you will beg for mercy because then I will use the leash and collar as a sex thing." Sirius promised. It was apparent that now he was completely giddy, much like a small child annoying their parents.
Remus- having a strong aversion to sex with any sort of toys whatsoever- shuddered at this possible outcome. That was, before he realised it wasn't possible at all. Sirius would get laughed out of Scotland if he wore that out in public.
"Fine, do it. I'll take you around on a leash for the next week. Your animagus is a dog anyway, it's not much of a difference." Remus laughed.
And that's how Sirius went around in a black studded dog collar for the rest of sixth year.
That's also how Remus became a lot more sexually adventurous. This will not be explained in further detail. Sadism and masochism is something that should be discussed in private and not in a scrapbook, I mean, Harry could see this stuff. Christ.
Loosely based from this piece of fanart I saw on DeviantArt ages back. Link shall be on my profile as this website hates me using actual links here. Ha, S + M, I could so write "50 Shades of Grey" better than that other thing did.
That is a joke. S + M scares the living daylights out of me.