AN: Some R/S fluff that seemed like a good idea at the time. Mainly plotless and for my own amusement.
Disclaimer: JKR owns everyone/everything you recognise.
Edit: My sort-of-beta, sort-of-stickler-friend has pointed out the issue with prefects (because I am lazy/unwilling to double check such things) so changes have been made. And she has been poked with a metaphorical stick for being the Potter Obsessive she is. And also, reluctantly, thanked.

Tartan Tribulations

"It seems to me, Lupin, that you have rather outdone yourself this time."

Remus isn't sure who he hates more; the inventor of the invisibility cloak or Sirius Black. The prefect bathroom is supposed to be private. That is the point of having it, after all. It offers hard-working prefects like himself the chance to indulge in a bath full of all sorts of delightful things and scrub chocolate off his school tie at the end of a rough, rule-abiding day. He is supposed to relish his duties and their rewards.

McGonagall twitches one eyebrow and manages to make it look intimidating. In his current situation, Remus thinks anything would be intimidating. "I must say this is rather out of character."

"Um. Yes."

"Were the bathrooms empty of towels, Lupin? Or did you mislay your night clothes?"

"Something like that." Remus can't quite bring himself to look her in the eye for fear of making his predicament any worse, though how much worse being found skulking around the castle sans clothes can get is up for debate.

The only issue with the prefects' bathroom is that someone decided it was only right to open up its luxuries to Quidditch Captains, and this means that Remus has to put up with James, who described the bathroom as 'poncy' and ridiculous until he discovered that Evans was also amongst the elite and all complaints suddenly vanished. But the problem with having James mingling with prefects is that when a person is as closely linked to Sirius Black as he is, you probably don't want them particularly close to any position of power. The same could be said for Remus, to some extent, but he isn't quite the troublemaker James is – or at least he isn't as loud about it – and besides, his immediate thought when faced with patrolling the corridors isn't 'let's see if we can lock Snivelly out of his common room all night' as James' certainly would be, but rather 'I wonder if I'll get to finish that report for Defence before bed.' Similarly, he does not think 'I wonder if I should follow Black's every whim and steal Moony's clothes while he bathes' when retiring to the prefects bathroom.

McGonagall conjures a tartan dressing gown with the disturbingly calm air of someone who has dealt with much stranger situations at past eleven at night, and hands it to him while keeping a straight face. Remus is more than grateful.

"Would you care to explain why you're out of bed at this hour, Lupin?"

He's glad that she's gone for that question first, rather than inquire as to why she saw him skitter around a corner with the desperate look of a man trying to hurry whilst preserving the remains of his dignity. He shuffles on the spot. "I was in the prefects' bathroom, Professor."

"I see." She scrutinises him, searching for the hint that there's a bigger plot at work here. "It's customary, I believe, for one to put clothes back on after a bath."

"Well yes, Professor, I quite agree."

"And yet here you are."

"Yes."

"Well." She says, after a moment of contemplation. "And why is that, Lupin?"

"I... I'm not entirely sure, Professor." It's not a lie, he decides; he isn't sure. He can, however, take a very good, very well educated guess and blame this on James and Sirius with little guilt. James, traitor that he is, has somehow done away with an entire cupboard of towels and Remus' robes for Sirius' amusement. Remus finds himself discreetly peering around the corridor for the tell-tale shimmer of the invisibility cloak.

The professor sighs wearily and tightens her own dressing gown. "Well, whatever is to blame for this unfortunate turn of events can be dealt with in the morning; perhaps a talk with your friends would be enlightening. I rather think it's best if we just overlook this little incident, don't you?"

"Oh, of course."

"I trust you can find your way back to Gryffindor tower with a tad more haste, now?"

Remus tells himself he imagines her slight smirk, and nods. "Yes, Professor. Um. Thank you."

"Goodnight, Lupin."

When she's disappeared around a corner and Remus is sure she's out of earshot, he turns around and glares at the empty corridor. "Alright, come on." Nothing. Not even a shuffle. As well as running around naked, he is possibly about to make even more of a tit of himself by shouting at thin air. "Sirius, I know you're there." He hisses. "If you don't reveal yourself in the next minute I swear I will cause you considerable pain, physical or otherwise."

There's the snort of barely contained laughter from his left and then Sirius' head appears, all shaggy hair and teeth. "Not one to be talking about revealing yourself at present, mate."

"You bastard."

Sirius shakes his head, grinning as he folds the cloak away. "You should've seen the way you skidded around that corner."

"Give me my clothes."

"They're back in the dormitory."

Remus blinks in a way that threatens many things, all unpleasant. "This castle is fucking freezing and it's your fault I am clothes-less in the first place. I demand trousers." The castle has got decidedly less freezing since Sirius started smirking at him like that, it has to be said.

"I rather think tartan suits you, Moony. Brings out your eyes."

Remus glares a little. "Do you know what could've happened if anyone other than McGonagall saw... saw me? It would've been awful, Sirius!" He means the multitude of scars, of course, but Sirius knowingly dodges the indication with the shrug of one shoulder and the way his eyes drop pointedly. He cocks an eyebrow, and Remus squints at him. "I shan't forgive you." The dressing gown really is hideous.

"I may be brilliant, but I can't take all the credit; our dear Prongs did the honour of nicking your clothes. Who'd have thought having you on the prefect team would prove so entertaining?"

"I'm glad this evening has been amusing for one of us."

Sirius seems to have gone from being a few steps away to being a few inches away in the course of the last two sentences and Remus is definitely not feeling the cold any more. "Amusing is one word." Sirius does that thing, the half-smile that quirks one side of his mouth up and makes Remus want to kiss him – and he gets the distinct feeling he knows it does – and then catches Remus' fingers in his own. "I could think of others."

"Could you?"

"Mhmm."

"Don't look at me like that. This dressing gown really doesn't merit it."

"Dressing gown doesn't have to stay if it doesn't want to." He does the thing again, which is a problem for Remus as it makes it very difficult to maintain an annoyed frown.

"Oh, I think it does. I'm not about to freeze my arse off in a corridor for anyone. Not even you."

Sirius ignores him. He brushes his nose against Remus' jaw, up towards his left ear. "No, I definitely think it's outstayed its welcome." Sirius has the dressing gown cord in his hands and uses it to tug him closer.

"Y'know, all I wanted was a bath." Remus wonders briefly if the tartan monstrosity is only on loan.

"You got your bath. You just didn't get your clothes."

"You're a prat."

Sirius hands are cold as he slips them inside the dressing gown and around Remus' waist. "And you're warm."

Remus swallows. "McGonagall's probably still prowling. Or Filch and that bloody cat."

"Is this train of thought going anywhere interesting?" Sirius has wormed one hand further up now, cool and feather-light against Remus' side. The other comes to rest on his hip.

"It's freezing. I'm wearing nothing but a dressing gown, not even my own, which I hasten to add is all your fault. And we're out of bed after li-" The rest of that sentence is deemed too sensible and boring by Sirius' mouth and as Remus is pushed back against the wall it seems the rest of Sirius agrees. And honestly, it seems a little unfair that kissing him still makes Remus' brain forget anything remotely intelligent.

"You were saying?"

"No." Long fingers trace the crescent shaped scar across his hipbone. He looks down at Sirius – something he's only been able to do for a couple of months and takes a small sense of smug satisfaction in, though he's only marginally taller – and grins. "Wasn't saying."

"Well. Good."

"Mm, I think so." Remus kisses him again, and decides that maybe, humiliation and forced tartan aside, he can forgive him for the clothes-stealing after all.