Sirius's heart pounds as he sits gingerly on the edge of the bed in the Shrieking Shack. He quickly gets up again, and goes to lean against the wall instead. The bed is the only unbroken piece of furniture in the house, but he feels he might create the wrong impression by sitting there when Remus arrives - as if proximity to the place where they have been intimate will somehow taint the purity of his errand. Not that they haven't against this wall a time or two -

He hears the floorboards creak downstairs, and he begins to sweat. Slow footsteps make their way up the stairs. For a panicked moment, he considers hiding, but he knows it is far too late for that. Remus will know he is here, this close to moonrise.

Entering the room, Remus's eyes find him at once, and a low growl escapes his throat.

"What the hell are you doing here?"

"It's the full moon," Sirius replies. "Where else would I be?"

"Get out, Sirius," Remus spits at him. "Now."

Sirius crosses his arms. "No."

"You forfeited your right to be here a month ago." Remus turns his back sharply and starts to undress, shrugging out of his robes and pulling his shirt off over his head. "I estimate you have thirty minutes at the most to get out of here, or I won't be held responsible for the consequences."

"Are we through, then, Moony?" Sirius asks softly. "You and me?"

Remus turns to stare at him. He's wearing the perfectly-schooled mask he always uses to hide strong emotion. Sirius can read nothing in it.

"I don't know," he says at last, lowering his eyes. "I guess that depends on - I don't know."

Sirius takes courage from his apparent indecision, and steps toward him to lay a hand on his shoulder. He can see a latticework of new and unfamiliar scars, still red and livid, all down the boy's torso, and the guilt squirms in his gut again.

I wasn't there for you.

Remus flinches and pulls away. "Don't touch me," he says, but the heat has gone out of his voice.

"Tell me, Moony," Sirius pleads, voice still soft. "I'm not leaving until you tell me we're through."

"Look -" Remus begins. Sirius can tell that it is becoming harder for him to focus with every passing moment. "Sirius, I - I can't - I have to think about it," he says. "I can't decide - can't think right now." He shakes his head, trying to clear it.

"No, Moony." Sirius lays a hand on his arm, and this time he does not pull away. "You don't have to think. You know. And I need to know. What does your heart tell you?"

Hesitantly, he moves his hand to Remus's chest, wistfully tracing a letter "S" over the boy's heart with his finger.

Remus does pull away at that, and goes to sit on the bed, rubbing his hands through his disheveled hair.

"Don't do this now, Sirius," he says in a muffled voice. "I'm not ready to forgive you yet. After what you did -" his eyes burn into Sirius as he looks up "- using me like that in one of your pranks for some stupid, petty vendetta against Severus -"

"I've said I'm sorry, Moony."

"You're sorry. You're sorry." Remus's voice rises, and the growl is back in it. "Do you have any idea what you're sorry for? Do you even knowwhat could have happened?"

"It was stupid," Sirius admits, hanging his head. "Snivellus could have been hurt or killed. You got hurt." He looks up. "I'll never forgive myself for that."

"No." Remus stands and strides back across the room, grabbing Sirius by the shoulders hard enough to bruise, and giving him a shake that forces Sirius to look him in the eye. "That is the very least of what might have happened," he says, voice shaking. "Yes, Severus could have been killed. And do you know what would have happened then, Sirius? Did you think about that?"

Sirius looks at him blankly.

"No? Well, let me tell you, Sirius-my-love. There would have been an inquiry. The Committee for the Disposal of Dangerous Creatures would have been called in to investigate. You might have been expelled. Dumbledore would almost certainly have been sacked for allowing someone like me on school grounds. And I would have been put down like an animal. The Ministry aren't big on second chances."

Sirius can feel the blood draining from his face, and he shakes his head violently as if to deny the truth of what Remus is saying. His knees buckle, and he sits down hard on the floor with a thump. Remus does not try to catch him.

He had thought he could not possibly feel any worse than he has this month, but he was wrong. A great, yawning chasm filled with horrors of which he had not previously been aware is opening at his feet. His head swims and he feels sick to his stomach.

Remus. Dead. My fault.

"So do you see, Sirius," Remus continues, "why 'sorry' isn't going to be good enough?"

"I'm the dangerous one," Sirius whispers through pale lips. "I did it; not you."

"I doubt that argument would have swayed the Committee," Remus says coldly.

Sirius looks up at Remus, eyes wide. "But you're Moony!" he says. "You're not dangerous! They would have to see -"

"Not dangerous?!" Remus explodes. "How can you say that? You, of all people, Sirius -? You know me better than anyone! At least I thought you did. Maybe we are through." He turns away.

Sirius bows his head in shame. "Please don't say that, Moony," he says quietly. "I've said I'm sorry. Please, just tell me what I need to do to make it up to you, and I'll do it. I'll do anything. I swear. Just don't be like that."

Sirius looks up mournfully to see Remus staring down at him, the wolf burning gold in his eyes.

"I need you to understand, Sirius," he says. "But if you don't already, I'm not sure you ever will."

"Teach me, Moony. Please? Make me understand."

Remus narrows his eyes, as if weighing Sirius's sincerity. "Be careful what you wish for," he says, voice filled with soft menace. "Sniffing after werewolves - you could end up hurt."

"I'm not scared," Sirius says bravely, knowing the wolf can smell the reek of fear coming off him in waves.

"And that's just the problem," says Remus. "You want to understand? All right, then."

Reaching down, he grabs Sirius by the shoulder and pulls him to his feet. Sirius knows Remus is stronger than he looks, of course, but the effortlessness of the action surprises him.

"Lesson the first," Remus says evenly, fixing him with an unblinking golden stare. "The wolf is strong. Stronger than you. If the wolf wants you dead, there's not much that can stop it. Even armed with silver, you're still pretty much fucked."

Sirius nods meekly. He cannot bear the cold look in Remus's eyes. He reaches out a hand to brush a lock of hair away from the boy's cheek.

With lightning speed, Remus spins him around and locks an arm across his throat. "Lesson the second," the cold voice growls in his ear. "The wolf is fast. It acts on instinct. It does not make choices."

Sirius feels teeth close on his neck, and holds very still. Remus is unpredictable in this state. He stays tensed, ready to change when Remus does, otherwise he is dead for certain. As it is, he can barely breathe.

Without warning, Remus grabs his wrists and twists both arms roughly behind his back. Sirius bites his lip and squeezes his eyes shut against the pain.

"Lesson the third," the cold voice continues, so close that Remus's lips brush his ear. He shivers involuntarily. "The wolf is not your friend. It exists to hunt and kill. It revels in blood and exults in death."

Remus twists hard again, crushing Sirius's wrists in one hand and forcing him to his knees. He kneels behind him, pressed close against his body. Sirius can feel his arousal, hard against his thigh. Reaching his free hand around Sirius's waist, Remus fumbles with the flies of his trousers.

"Lesson the fourth. The wolf does not ask permission. It takes. It does not love."

Sirius keeps his eyes shut tight, shivering as the cool air strikes the skin of his thighs, resolved to take his punishment like a man, in silent acceptance.

I won't cry out, he tells himself stubbornly. I won't ask him to stop. Not that he would -

He feels Remus fumbling with his own trousers, yanking them impatiently out of the way. Then Remus's cock is pressed hot and insistent against his bare skin. He bites his lip, heart pounding.

"The wolf takes what it wants." Remus is panting now. "It fucks who it wants." He wraps his free arm around Sirius's throat once more to hold him still. "Do you want the wolf to fuck you, Sirius?" he growls.

Sirius can manage no more than a tiny shake of his head.

"That's too fucking bad then, isn't it?"

Sirius cannot suppress a strangled cry of pain as Remus ruthlessly enters him. They overbalance, falling forward so that Sirius fetches up with his cheek pressed against the splintered floorboards, Remus heavy on top of him, thrusting with rough abandon, growling low and continuously in his throat, teeth sunk into Sirius's shoulder.

Sirius cannot decide which is worse; the pain in his arms where Remus is twisting and crushing them, or the burning pain in his arse as Remus relentlessly fucks him. But neither can compare to the knowledge that it is Remus - his Remus - doing this to him, getting off on his pain and fear and sorrow. A tear squeezes out from under his eyelid and fades unnoticed into the dust on the floor.

An eternity later - though in reality, it is probably no more than two minutes - he feels Remus groan and shudder against him.

He is still for a moment before pulling out of Sirius, standing up, and coolly removing the rest of his clothes. Sirius continues to lie on the floor, eyes shut tight, not moving, hardly daring to breathe, trying not to feel.

"Lesson the fifth," Remus's voice is hoarse. "The wolf is in me, always. I am dangerous. Never forget it."

He turns and strides out of the room, slamming the door behind him.

As Remus's footsteps echo down the stairs, Sirius transforms into Padfoot and slinks painfully under the bed, tail between his legs, to wait for the dawn.