Filch shot them one last gloating look before shutting the heavy door to his office. The tumblers clicked as he locked the two boys in before hastening down the corridor after Mrs. Norris. Once his footsteps had faded Sirius grinned at Remus and leaned back in his chair, balancing on the back legs.

"Don't start," Remus warned. He didn't bother looking at Sirius, just bent to the task at hand-copying old detention cards from the large, overflowing box Filch had dumped in front of them.

"Come on, Moony. I've always wanted a good long look around Filch's inner sanctum. This is a perfect opportunity for mischief," Sirius said, bringing his chair back down with an obnoxious thump and leaning toward Remus. "Might be our last chance, after all."

"I should be so lucky. And your last 'opportunity for mischief' ended us up here, right now, may I remind you," Remus retorted. "If you recall, I tried to talk you out of it then, too."

"Don't be such a wet blanket!"

Remus's mouth thinned. "Sirius, you know that I wanted to study for the potions exam tonight. You know when it is, and you know that I will be unable to study much at all the rest of the week. Yet you still insisted on hexing Avery and Mulciber in the middle of the corridor, in broad daylight, right around the corner from the Transfiguration classroom, where McGonagall was currently teaching a class of first years, despite me telling you to walk away from it. And," Remus continued (rather shrilly Sirius thought), "you dragged me into it besides."

"Relax, won't you? You'll get it done." Sirius nudged the card Remus was filling out, causing his quill to skitter and scratch a line of dark ink across the form.

Remus glared. "Oh, really?" His voice feigned astonished excitement. "You've discovered an immediate cure for lycanthropy then? Why didn't you say so!"

"No." Sirius scowled, not liking the reminder that he was powerless to solve that particular problem. "But I'll help you. I'll go over notes with you and test you."

Remus snorted, pulling a fresh card from the pile. "Right. Because you're always such a help with things like that."

"What's that supposed to mean?" Sirius sat back, looking rather affronted. "My marks are ace and you know it."

"Yes, yes. You're brilliant." Remus rolled his eyes. "That doesn't mean you aren't an arrogant berk who thinks himself too good for revising." Remus paused in his task for a moment and straightened. For a moment he was still. Then he tilted his head, his expression taking on a haughty cast, and tossed backed his hair in imitation of Sirius. "I don't need to look at that rubbish," Remus said in scathing tones. "I know it all." With a pointed look at Sirius, Remus picked up the quill again.

Sirius gave a grudging laugh. It really was a good impression of him, not that he would ever admit it. "Aw, Moony. I'm not that bad. You know I'll give you a hand."

Remus made a soft sound of disbelief. "Give me a hand with our detention, why don't you?" He shoved a stack of cards toward Sirius.

"Hopeless," Sirius sighed. Pushing back from the table, he surveyed the office. From his place he could see Filch's desk piled up with stacks of paper and confiscated items. The drawers had locks but Sirius was sure those wouldn't pose a problem. The good stuff was definitely going to be kept under lock and key. There were also several ancient looking filing cabinets, presumably filled with the countless misdeeds of past Hogwarts students. Though, doubtless, none of them could stand up to their own exploits. The cold, stone walls were empty of anything save a lone pair of shackles attached to chains and a sturdy-looking iron hook that connected high enough to make any unfortunate captive stretch uncomfortably.

Sirius grinned at that. "Hey, Remus. I reckon Filch must be a right kinky bastard. He's always going on about chains and beatings, and how students should be punished the old-fashioned way." He stood and moved behind Remus, bending over to murmur against his ear. "Where do you think he keeps his whip?"

"You're sick, Black." Remus said, turning his head to look from Sirius to the shackles. "I don't ever want to think about Filch's sexual proclivities of any sort. So, really, thanks for that." His mouth twitched up at the corner, though.

Sirius laughed. "You're right. That was cruel of me." He nuzzled against the skin beneath Remus's ear then placed several teasing kisses down the curve of his neck. "Let me replace those nasty thoughts with something else."

Remus shivered a little, but pulled away. "Sirius," he warned.

"What?" Ignoring the protest, Sirius slid his hands down Remus's chest and all but purred in his ear. "If you don't want to explore, I can think of something else we can do."

"No," Remus said. "That's-stop that," he grabbed at the hand Sirius was snaking lower. "Filch could come back any time, and-"

"He won't. You know it. James and Peter will be distracting him for a good while yet." His palm settled over Remus's crotch and he squeezed lightly through the fabric of the school trousers.

Remus hissed, involuntarily tightening his grip on Sirius's hand. "Just because you've dragged the Head Boy into providing cover for-ahhh!" Remus groaned, struggling with himself for a moment. Then, with a momentous effort at self-control he twisted around and pushed his chair away from Sirius.

"I mean it, Sirius. We're going to get caught, and then we'll not just get detention. We could be expelled and I really can't-"

"Shut up," Sirius said, and then he made sure of it by fisting the front of Remus's shirt and pulling him up and forward. His mouth slanted against Remus's full, startled lips and it wasn't hard to lick his way inside and kiss Remus the way that always made him go flustered and languid and wanton. He released his hold on the shirt and threaded his hands through Remus's shaggy hair as Remus settled his hands on his hips and tugged Sirius closer.

They were both breathless when they finally pulled away from each other. Sirius was looking smug and Remus resigned but smiling.

"I think you're right, Sirius." Remus said with an uncharacteristic smirk. "I think we should explore."

"Explore?" Sirius said, vaguely, as he watched Remus flick his tongue over his bottom lip the way he always did when he was working through the ramifications of some idea.

"Yes." Remus nodded. His expression firmed, and he planted a hand in the middle of Sirius's chest, shoving steadily until Sirius fetched up against the uneven stone wall. Before Sirius could say anything, Remus leaned in, biting at his mouth rather viciously. Sirius groaned, their teeth clicking together as they battled out the kiss. Without warning, Remus broke away and spun Sirius around, holding him there with his hips and chest as he pulled out his wand and muttered a quick spell. His wrists were secured in the shackles and the warmth from Remus's body was moving away before Sirius could even process what had happened.

"What the fuck?" Sirius tried to twist around but the chain was linked up high enough that he could only catch a glimpse of Remus over his shoulder.

"As I was saying," Remus continued as if there had been no interruption at all. "I think we should explore-" He offered a bright smile to Sirius. "-All the exciting possibilities regarding those proper punishments for students you mentioned." Sirius heard Remus cast one of his own personal locking charms at the door and then the click of leather soles as Remus walked across the room toward the filing cabinets. "I mean, maybe Filch is right after all. It's obvious these current punishments aren't very effective."

Sirius smirked in the general direction of Remus's voice. "So you're going to punish me then, Moony?"

"That's right," Remus said mildly, as if he was discussing the unseasonably warm weather with a shopkeeper in Hogsmeade. "By the way, I've found the whip."

The click-click of Remus's shoes came closer and Remus obligingly moved to a position that allowed Sirius to see the long, wicked-looking tail of tightly-woven black leather. His eyes widened as Remus stroked the tip against across one of Sirius's aristocratic cheekbones. "Looks well worn in, don't you think?"

"You're not really going to use that bloody thing on me, are you?" Sirius thought he managed to keep his voice in his normal register, but he did sound incredulous. Not that he really believed Remus of all people would have a go at someone with a sodding evil-looking whip.

"Don't you think you deserve it?" Remus moved behind Sirius, out of sight, The sudden loud crack-that Sirius really should have expected-made him jerk against the chains. Remus laughed.

"Remus." And now it was Sirius who sounded a warning through his voice and stiff posture. "Ha ha. You've had your laugh, so you can just-" He rattled the shackles imperiously. "Get me out of this, and we'll do the sodding detention the way you wanted to."

"Hm. Tempting offer, Sirius, but no." Remus prodded him with the tip of the single-tail and laughed again as Sirius twitched. "I've decided I'm quite on board with doing things your way. Well...with minor deviations."

"Remus...Moony." Sirius tried to twist around again. "There's a reason they banned this sort of thing, you know! Be reasonable!"

"That's a laugh coming from you, Padfoot. But don't worry yourself." Remus stepped closer and rubbed his hand in soothing circles over the small of Sirius's back. "I would never use this whip on you. I could take your eye out, or worse, mine."

"Oh, well, good. Right. Knew you were just taking the mickey."

"Yes," Remus agreed. Sirius heard the whip clatter to the floor, and he grinned against the stones as Remus's hands came around his waist and unzipped Sirius's trousers.

"I'm not going to use the whip," Remus clarified. "I'm going to use your belt." And with those words, Remus undid Sirius's belt and tugged it through the loops of the waistband, letting the trousers fall to the floor in a whisper of fabric, pooling around Sirius's ankles. A sharp tug sent his pants following, and Sirius was left dangling in nothing but a white school shirt and his Gryffindor tie.

"Remus! Ow! Ow." Sirius cried. "I cannot believe you-Ow!"

Remus paused to admire the effects of the first three blows. Sirius had lovely pale skin that really showed everything to wonderful effect-rare blushes, kiss marks, and, apparently, welts from well-deserved spankings. Sirius was sputtering indignantly.

"Lupin, you are going to regret the day you were born when I get out of this," he growled, one of those rare blushes shading over his face as he tried to glare over his shoulder at Remus.

"Oh, using surnames now, are we?" Remus tsked. "I think I'll take my chances, Black, as you certainly have done more to deserve your predicament than perhaps any student ever to attend Hogwarts School of Witchcraft and Wizardry. In fact, if anyone was to find out about this, I'd probably get an award for special service to the school. To Remus Lupin, it might say, for taming the incorrigible Mr. Black, or at least for giving him what for and making him cry like a little girl."

"I'm not crying!" Sirius roared.

Remus smirked. "Not yet," he conceded. "Shall we continue?"

Despite the many and varied protests and rude suggestions from Sirius, Remus did. He began to develop a smooth rhythm-sweep back, swing, connect, sweep back, swing connect-until it was almost hypnotic. Watching Sirius writhe, trapped against the wall and his chains, was unexpectedly erotic. Remus had really intended to just tease him a bit, give him a few sound spanks and let him go with threats to tell James and Peter about it later if he didn't behave for the rest of detention. But Sirius looked amazing like this. The skin of his arse was reddening, a deep rose shade across the perfectly-shaped cheeks, and Remus couldn't tear his eyes from the sight of it.

Sirius, too, had fallen silent except for helpless gasps and moans that went straight to Remus's cock. At first, Sirius's hips had bucked wildly as he futilely tried to evade each blow, but gradually something had changed. His hips still moved, but now it was in sync with the rhythm Remus had set. The air seemed heavy and charged, slowing everything and everyone into exaggerated motions and responses. Remus bit his lip hard. Watching the way Sirius was taking it-this from him-was mind-blowing, and making him unbearably aroused. His cock throbbed, uncomfortably bound in the confines of his pants. It made him want to push-just a little more. He began to swing harder, gritting out questions with the blows.

"Are you going to listen to me from now on? When I say something. When I say no?" Remus fought to keep his voice steady, though it was thick and hoarse.

"Yes," Sirius groaned, straining up on tiptoes as the stinging across his arse intensified.

"Are you going to stop fighting so much. Learn to walk away when it's not important. When it doesn't matter?"

"Yes." Sirius shuddered out something like a sob, nodding furiously. "Yes...God."

Almost dazed with lust, Remus pulled in a deep breath, fascinated by the skin that was starting to raise and welt.

"You'll learn to think. You'll remember this...think about this..." Remus demanded, snapping the belt sharply. "Say it."

"Oh...will...yes." Sirius writhed frantically. "Remus." His voice was so thick with need and want that Remus's breath caught and held in his throat. "You're mine," he whispered, rough and raw, He tossed the belt aside and went to his knees behind Sirius, grabbing his hips and licking at the tender, red welts he'd raised.

Sirius mewled, and Remus had to grip harder to contain his thrashing, sure those hips would bear finger-shaped bruises by morning. "Please," Sirius begged, his voice ragged and desperate. "Please, Remus."

In a flash, Remus was on his feet dropping the chain a few notches and twisting Sirius around to face him. Sirius spun, hissing as his arse scraped up against the stones and his wrists crossed overhead, his trousers still tangled around his ankles. He had never looked more beautiful. Remus took in the wide-open pupils, the flushed cheeks, the stretched and quivering limbs and, oh...He fell to his knees again, face to face with Sirius's gorgeous, perfect cock that jutted forward from underneath the hem of his shirt, so very hard and glistening at the tip. Sirius made some desperate, needy sound, and Remus swallowed him, sucking and licking and tasting while Sirius threw his head back, heedless of the hard stone wall.

Unable to resist, Remus curved his fingers around the globes of Sirius's arse, kneading and tormenting the bruised flesh as he sucked Sirius harder and deeper. Sirius cried out, arching off the wall helplessly as he came down Remus's throat in intense throbbing spurts. Then Remus was rubbing his own cock in frantic urgency, unable to manage even undoing his zipper. His release came fast and hard and he rested his forehead in the hollow of Sirius's hip, panting harshly.

After several moments, Remus felt like he might be able to stand, and he pushed up and somewhat hesitantly met Sirius's eyes. They were bright and a little wild, but the expression in them surprised him. They held a tender and sated look, but also a hint of shock and awe and maybe...a new kind of respect. He found he quite liked it. It was an expression he'd definitely like to put there again. But right now he just wanted to kiss that impossible, curving, perfect mouth. So he did.