Title: So Scared Of Breaking It
Rating: NC-17
Word Count: ~1600
Pairing: Sirius/Regulus
Please Be EnticedWarnings: INCEST, gay sex (semi explicit), breathplay, kinkiness, possibly underage(I mean how long does Regulus live anyway?)
Summary: -just a little more then. He knew he shouldn't but he twirled the satin strings around his fingers and pulled tighter.
Author's Note: This is my first ever Sirius/Regulus fic *is nervous*. elainemalfoy thank you for betaing this cestiness lol. I used the prompts corset and puppet master. Written for 7spells on LJ. Anyway I really hope someone out there enjoys Blackcest as much as I do *is awkward*

Sirius felt a drop of water land on his hand and he looked up. From this angle he could see his brother's cheek lined with kohl black tears.

Sirius smiled— just a little more then. He knew he shouldn't but he twirled the satin strings around his fingers and pulled tighter. Regulus jerked forward, his usually pale angular shoulders were now a sickly purple color. "Relax," Sirius murmured while pressing his lips against the skin of Regulus' shoulder.

Regulus shuddered, "Why—why are we doing this?" His voice was airy, delicate. Heat flooded to Sirius' erection; he could easily snap Regulus in half yet Regulus trusted him not to, that kind of power was exhilarating.

"You wanted it, remember?" Sirius forced himself to let go of the satin strings. It was enough. He had to resist the urge to pull the corset tighter. If he didn't, Regulus could pass out, break a rib, or even die and Sirius wasn't exactly sure how he'd explain that to Madam Pomfrey.

"I—I wanted—I didn't want—this," Regulus gasped.

"You didn't want what, Regulus?" Sirius asked innocently. "The corset or the cock? You said I could put it wherever I wanted. You begged me to."

"I did, but-" Regulus coughed, "-but you're so—so violent, worse than me. If mother and father knew—if your friends knew—"

"Hush, save your energy," Sirius chided. He didn't even like to imagine anyone finding out about their little Thursday morning hobby. He knew people would be more shocked by his behaviour than Regulus'.

"But, Sirius, if—"

"But nothing," Sirius snapped dangerously.

"If they catch us—" Regulus abruptly went silent, and Sirius was startled to find his fingers wrapped up in the strings again. He took a deep breath, let go, and instead wrapped his arms around Regulus' narrow waist.

"I promised I was going to make you come, didn't I?" he whispered soothingly in Regulus' ear.

His brother nodded.

"The best orgasm you'll ever experience, I promised. Don't you trust me?" Sirius asked; he ran his hands over the length of the corset and his cock pulsed eagerly at the feeling of lace and frills.

Regulus nodded again, his breathing frighteningly staggered.

"Now don't make a sound, okay? I don't want you to run out of air." Sirius kissed Regulus on the neck, which was rapidly turning blue, and then he pressed Regulus hard against Slughorn's desk and slipped back inside.

Regulus groaned.

"Shh," Sirius hissed warningly and then he whispered, "feels good, doesn't it baby?"

"Sirius—I can't—I can't breathe," Regulus wheezed, lightly. The sound drove Sirius to speed up his movements; Regulus was already halfway to orgasm before Sirius made him put on the corset.

"'t's almost over. And—ungh so tight—and I can feel it, it'll feel so good." Sirius punctuated his words with the thrust of his hips. Regulus was slipping, his upper body falling forward towards the desktop. Sirius gripped at Regulus' protruding hip bones in order to keep him upright.

"Fuck," Regulus hissed.

"Exactly," Sirius replied. He reached around with one hand and grabbed Regulus' cock; it was so swollen it stood completely upright. Sirius squeezed it and Regulus responded by pressing his back into Sirius' chest. The lace fabric of the corset brought Sirius over the edge. He slammed into Regulus repeatedly, chasing his orgasm furiously at an erratic pace. He dug his fingernails into Regulus' hips and bit Regulus' shoulder.

Regulus cried out. His body jerked and twisted unnaturally. His hips moved frantically back and forth into Sirius' hand, using up nearly all of his energy. He came all over the desk and Sirius' palm only minutes later. He was shaking so roughly and screaming so loudly that Sirius had no choice but to come in response. Sirius didn't pull out right away, instead he let himself go completely soft inside of Regulus' arse. "'t's okay," he murmured into Regulus' back repeatedly. His brother was limp in his arms before he remembered to loosen the corset.

Regulus slumped against the desk, coughing and sputtering. "Sirius!" He cried out when he caught his breath. He turned to face Sirius.

"Yes?" Sirius asked softly, trapping his come stained fingers in Regulus' hair.

"I almost—you almost killed me."

Sirius smiled, "Don't be dramatic, Reg. I know you liked it."

Regulus shrugged away and began to loosen the ties of the corset so he could slip it off.

"Yea, I liked it— too much…" Regulus' voice trailed off.

Sirius found that fascinating, "I almost killed you Reg, and you liked it." He said, grinning.

Regulus shrugged his shoulders and looked down, "It hurt but it felt really good… it's weird…"

The normal flushed color flooded back into Regulus' cheeks; it was getting Sirius hard all over again. He bit his lip, however, when the corset came off to reveal Regulus' heavily bruised abdomen. He didn't realize he'd pulled it that tight. He traced his fingers over the fresh bruises and Regulus winced.

"Is anything broken?" Sirius asked.

"No…"

Sirius smiled, "See I told you you'd like it. Give me a kiss."

Regulus did as he was told. He leaned into Sirius' lips for a sloppy wet kiss and then pulled back shyly, his kohl rimmed grey eyes shining. "How did you know it would feel so good?" he asked.

"I can't tell you that." Sirius smirked. His brother's eyes darkened with jealousy.

"It was your fucking half-breed friend wasn't it?" Regulus growled sharply.

Sirius instinctively slapped him. "How many times do I have to tell you not to talk like that?" Sirius said coldly.

Regulus gripped his cheek; his eyes watered with bitterness and remorse. "Sorry," he muttered.

"If you keep it up, Reg, I won't let you come next time." Sirius ran his fingertips over Regulus' cock teasingly and smiled when Regulus inhaled. "In fact," Sirius continued, "I'd put you in the corset and tie up your hands until I'm finished with you, maybe even longer." He licked his lips.

Regulus' eyes were wide and fearful. "I'm sorry," he repeated, more emphatically this time, but it was too late. The thought had already been planted in Sirius' mind and he knew he'd eventually end up fucking Regulus that way, whether Regulus deserved it or not.

"It just so happens that the idea came from a pureblood," Sirius said.

"Potter?" Regulus inferred.

Sirius nodded and Regulus appeared impressed. He didn't worry about Sirius fucking James. As far as he was concerned James was as straight as they came. It was Remus who bothered him but Regulus knew better than to let it slip to him or anyone about what he and Sirius did behind locked doors.

"Well, I want to do it again."

"But you're sore." Sirius touched Regulus' bruised chest again. Regulus flinched. "I know but I—it felt so—"

"I know," Sirius interrupted; he wanted to see Regulus wrapped up in the contraption again as well. His cock tingled at the idea. His brother was oddly beautiful; he requested Regulus wear eyeliner for this very reason. The women wearing corsets in the dirty magazine James shared with him had all worn eyeliner. All the women in the photographs writhing and humping the men's cocks, Sirius had become so obsessed he began to see Regulus in those positions every time he closed his eyes.

Sirius smiled to himself and happened to gaze at the clock. He gasped. "Damn it, get dressed."

"But I want to-" Regulus followed Sirius' eyes to the clock, "fuck!"

They cleaned up and dressed rapidly in the silence. Regulus was the first one done and he turned to Sirius, his shoulders slumped petulantly. "Can we do it again? Tonight?"

Sirius slipped his arm into his shirt and then cupped Regulus' chin between his thumb and forefinger. "Slut," he whispered. Regulus grinned and Sirius drew him closer so that their lips met briefly. What they were doing was reckless, but for some reason Sirius was addicted to trouble. He pulled out his wand and swiftly cleaned the desk.

"Not tonight. I have—something." There was a full moon tonight, he couldn't really justify leaving his friends to spend time with a brother everyone believed he hated. "What about Saturday?"

"Can't," Regulus mumbled. "Quidditch."

"Well, Ill think of something. I promise." Sirius kissed Regulus once again, this time on the cheek.

Regulus nodded, disappointment evident in his posture, as he turned and walked out of the classroom. Sirius lingered a moment before taking his seat.

As usual, Snape was the first one to enter the classroom. His lip curled upwards into a sneer when he saw Sirius.

"Missed another opportunity to shower in favor of coming early, Snivellus?" Sirius asked snidely, resting his back against his chair.

Oddly enough, Snape ignored him and took his seat. Sirius shrugged and closed his eyes. He didn't want to lose the image of his brother in the lace corset.

"I knew you planned to squander your pureblood heritage, Black, but I wasn't aware you were that filthy."

Sirius' eyes snapped open. "Did you say something, Snivellus?"

Snape's black eyes glittered like he'd just discovered the Elixir of Everlasting life. "Now I understand why they say madness runs in the Black family. Toujours Pur, am I correct?"

A cold prickle crept up Sirius' spine. Perhaps he'd been a bit too reckless this time.