Author's Notes: Written for daysandweeks's "Hot Sauce – or, not so much" challenge. Bellatrix/Sirius. Smut, Blackcest.

I'm under no delusions that this is the best thing I've ever written, but I did have an indecent amount of fun doing it. Enjoy.


Bellatrix was miserable. She had spent the whole day out with her mother at a painfully dull party, which would have been all right on its own, but the event had culminated in Rodolphus Lestrange pulling her aside, and telling her that her parents had agreed to let him marry her.

Bellatrix had been shocked, of course; her parents had mentioned nothing of the sort to her. But Rodolphus seemed quite sure, and when Bellatrix cornered her mother and asked her where Rodolphus Lestrange got the idea that he was going to marry her, Druella had been matter-of-fact.

"Of course we didn't tell you until it was a done deal," she said. "You would have only complained and made life a misery for all of us." And no matter how Bellatrix protested and screamed, sobbed and begged and wheedled, she was still engaged to Rodolphus, and she had the diamond on her finger to prove it.

It wasn't that she hated Rodolphus Lestrange. He was a decent enough man, especially for a rich Pureblood. Reasonably kind and polite, and far from bad-looking. But he was so…

Bellatrix shut the front doors of the Manor behind her, and started for the library, where she could sulk in peace.

Or, that had been the plan.

Her cousin, Sirius, was stretched out on the couch, reading, and when he saw her, he shut the book and glared. "Thanks for knocking, cousin."

"It's not your library," Bellatrix snapped, pushing his legs off the couch and sitting down.

"Might as well be, I'm the only one who ever reads in here."

Bellatrix pulled her wand from her pocket and aimed it at Sirius. "Get out, you little brat."

"Make me."

She slashed her wand through the air, and Sirius yelped as her spell burned him. He rolled off the couch, landing with a painful thump on the floor, before standing up and moving away from his cousin, clutching his arm.

"Bitch," he snarled.

"Brat," she replied.

Sirius stamped out of the library, slamming the door behind him, and Bellatrix stretched out on the couch where her cousin had been lying. It was still warm from his body, and Bellatrix squirmed a little to get comfortable against the heat.

Just like Sirius to push her when she thought her life couldn't get any worse. Stupid little boy, didn't he understand that sometimes it was better not to pick fights?

Of course, he had probably learned the always-ready-to-fight approach to life from Bellatrix herself. She didn't like to admit it, even in her own mind, but if she respected Sirius far more than she felt that she should. If only he hadn't gone and made friends with all those Gryffindor boys and gotten himself into Mudblood rights and all that.

But who was she trying to convince? She thought Sirius was as near perfection as anyone male could be – he was intelligent and brave, and even if she didn't agree with his ideas about Mudbloods and blood traitors, she had a certain grudging admiration for his conviction. And then, of course, there were his looks…

Sirius, like Bellatrix, had traditional Black features – thick, dark hair, strong jaw, clear, pale skin, and a tall, slender build. And in Sirius – at least, in Bellatrix's opinion – these qualities were at their finest. Much as she wanted to hate Sirius, she had to admit he was handsome. Very, very handsome.

She tried to pull her mind away from her cousin's looks. Rodolphus. She was angry about being married off to Rodolphus. Yes. Anger was good. Being angry was reasonable, where feeling an attraction to one's cousin was not. Think about Rodolphus. Think about being angry at Rodolphus.

But Rodolphus's face turned to Sirius's in her mind's eye, and much as Bellatrix tried to keep such thoughts out of her mind, she couldn't help wishing that the things she would soon have to do for Rodolphus she could do for Sirius instead…

Sirius slammed back into the library, and stood in front of Bellatrix, arms crossed and foot tapping. She looked at him, very annoyed. Hadn't he already been enough of an annoyance for the day? Did he really have to interrupt her again? While she was enjoying one of her fantasies – and about him, no less.

"I left my book," he said shortly. Bellatrix picked it up from the floor where he had put it down, and smirked when she saw the cover. It was an old thing, ratty and dog-eared, with a title proclaiming it was about "Notable Blacks of the 14th Century", but Bellatrix knew full well that it was, in fact, a compilation of stories of the various sexual encounters of a hundred years of Blacks, written in pornographic detail, and enough to make one blush for hours after reading it.

She held it out of his reach. "Ooh, Sirius needs his erotica, does he?"

"Give it back," Sirius snapped. "You're not funny."

"Your parents wouldn't be at all pleased if they knew you'd been reading this," Bellatrix sang, stretching the arm with the book so that Sirius had to lean over her to grab at it. "If you don't want me to tell them, you ought to be a little more polite to me."

Sirius climbed onto the edge of the couch, and managed to catch one corner of the book. "Give it back!"

Bellatrix slapped his hand away, and reached both her arms above her head, holding it tantalizingly out of her cousin's reach. "Make me."

Sirius swung one leg over Bellatrix's torso, sitting on her to pin her still, and grabbed the book, wrestling it out of her grasp.

Bellatrix held on for a moment, then let it go, moving her hands instead to rest on Sirius's thighs.

"Brat," she murmured, drawing light circles on his legs with her fingertips.


There was a silence, Sirius apparently unsure what to do. Bellatrix looked up at him through lowered lashes.

"You don't need that book," she said, moving her hands from his thighs to his groin, and stroking him through his trousers.

Sirius seemed only to have just realized the innate sexuality of their position. But he made no move to stop her. Bellatrix gently moved her hands up his sides, rested them on his stomach for a moment, before setting to undoing the buttons of his shirt. Sirius seemed frozen, equal parts petrified and mesmerized, and only Bellatrix had his shirt undone, and was running her fingers over his chest, with mounting excitement – Merlin, he really is a perfect man – did he move at all.

Sirius dropped the book, and his hands went to Bellatrix's breasts. She arched her back, grinning devilishly. Rodolphus was fast losing any chance of getting a virgin on his wedding night.

With no small amount of effort, Bellatrix managed to wrestle Sirius so he was the one lying on the couch, and she was over him. Yes, she preferred this, being on top and in control. Sirius started to protest, but she silenced him by pressing her mouth over his. And she shifted so that she was rubbing against the swell in his trousers.

Sirius scrabbled at the fastening of his trousers, and Bellatrix pulled her own skirt out of the way, heart hammering with fear even as she kissed and felt and caressed her cousin. She could scarcely believe Sirius was so… willing. She had never expected it to get this far.

She sank down on Sirius's cock, and bit back a cry of pain as her maidenhead broke. Much as she was assumed to be promiscuous, Bellatrix was, indeed, a virgin – or, she had been.

Sirius groaned, eyes squeezing shut and hands tightening on Bellatrix's hips. She took a moment to adjust to the pain and the strange feeling of having something inside her, then slowly rocked her pelvis back and forth, finding a rhythm that felt natural to her. She slid up and down his shaft, and Sirius clutched at her, trying to force her to move faster, harder. Bellatrix slapped his hands away. She may have been new to this, but she wasn't going to let her cousin control her.

Sirius didn't last long. He came violently into Bellatrix, palming her breasts, his face contorting into an expression unlike anything Bellatrix had seen before. She liked the feeling of his come inside her, even if she might have wished for the act to go on longer.

Sirius pulled out, and pushed Bellatrix backwards so that she was sprawled on the couch, skirt up about her hips. He put his mouth to her, and lapped up the blood of her virginity before setting to work pleasuring her. His clever tongue swirled around her clit, and Bellatrix, who had trained herself through many years of self-pleasure to be able to climax relatively quickly, didn't find it difficult to come against her cousin's mouth.

Sirius pushed himself up, and lay over her, toying with her breasts, and breathing heavily into her ear.

"Didn't realize you were a virgin," he whispered, rolling one of her nipples between his fingers. "If I'd known that, I wouldn't have done it."

"Brat," Bellatrix panted.