Author's Notes: Written for blood sugar love's Flavour Prompt Challenge.

Warnings: Sex, masturbation, voyeurism, threesome, incest.

)O(

Rodolphus was out of bed, after hours, with Bellatrix Black.

Rabastan did not like this.

Jealous by nature, and – like every other human being in Hogwarts school – wildly attracted to Bellatrix, he despised the fact that his brother was out with her. Especially at night.

He didn't like to think what they were getting up to.

No, that was a lie. He liked very much to think what they were getting up to.

It was almost midnight by the time Rabastan surrendered to his curiosity. Bellatrix and Rodolphus had left the common room barely past seven o'clock, and he felt that after nearly five hours, he had restrained himself long enough.

He crept from the common room, tiptoeing through the corridors, alert for even the slightest noise – either to indicate that a teacher might be approaching or that Bellatrix and Rodolphus might be nearby.

It didn't take long for him to hear them. They weren't exactly being quiet.

On tiptoe, Rabastan crept towards the classroom from which Bellatrix's soft, throaty moans were emanating. The door was slightly ajar, and moonlight spilled from the crack around the frame.

Rabastan looked inside, and immediately half-wished he hadn't.

Bellatrix and Rodolphus were there, all right. Bellatrix was up with her back against the wall, and Rabastan was pressed unbelievably close to her, the two of them locked in a deep kiss. Bellatrix's ample breasts heaved against Rodolphus's chest.

Rabastan couldn't quite hold back the tiniest of moans. He could scarcely imagine what that felt like – to be pressed so closely against Bellatrix's body that there wasn't even a molecule of air between them. As he watched, Bellatrix broke the kiss to shake back her hair, and her every motion looked so beautiful. She was like a goddess.

And Rodolphus… so strong and powerful, pressing her against the wall. What Rabastan wouldn't have given to be like that. His brother was every bit as beautiful as Bellatrix, really, in his own way.

"Roddy," Bellatrix purred, lifting one leg and coiling it over Rodolphus's. "Oh Roddy…"

Roddy, Rabastan mentally scoffed. He actually lets her call him that?

But Rodolphus seemed to have no complaint. He just slid his hand up under Bellatrix's short school skirt, clutching her thigh as he hoisted her a little higher between himself and the wall. She was now nearly immobile, her body flattened against the stonework, barely grazing the ground with the toe of one shoe. This new position gave her about two inches of height over Rodolphus, and he had to tip his head back to kiss her. Her pretty, pale hands tangled in his hair and she wrenched his head back so he was facing up to her.

Rabastan, to his profound horror, felt a twitch in his groin. He looked down, and swore under his breath at the bulge in his trousers. But he had no time to dwell on it, because a second later, his thoughts were interrupted by Bellatrix's velvety-smooth, seductive purr.

"Rodolphus… I need you… you don't know how much…" she whispered, the words ending with a breathless little giggle as Rodolphus's fingers slipped still higher up under her skirt. Her legs went around him, locking around his waist. "Give it to me, Roddy, I want it bad…"

"You're so eager," Rodolphus teased, and Rabastan felt another flash of arousal. He wished he was the one being talked to like that… no, he wished he was the one talking like that. Yes. He wished he was the one talking like that, with Bellatrix pressed between him and the wall.

"I am, I am," Bellatrix nodded, squirming in excitement. "Come on, Rod… I know you're man enough… and I can tell you're just as eager as I…" one of the hands that had been tangled in Rodolphus's hair slid down his face, his neck, his well-muscled chest, and then down to his crotch. Rodolphus's body blocked from Rabastan's view exactly what she was doing, but Rodolphus let out a low moan and Bellatrix giggled, so Rabastan had a very good idea.

"Even more eager than I am," Bellatrix continued. "You're… so big… and hard…"

Rabastan shut his eyes for a second, then opened them again, fixing them on his brother and on Bellatrix. He could help – and didn't want to – imagining that he was the one being told that. Against his will, his hand moved down to his tented trousers, and he touched himself lightly. His cock trembled through the thin fabric and his breath caught as Bellatrix continued speaking.

"I want it, Rod," she breathed. "Your cock… I want it in me… big and hard… pounding into me until I scream…"

"You can be such a slut sometimes, you know," Rodolphus murmured, and Bellatrix laughed, squirming against him. "I am… I'm a dreadful slut… but that's what you like about me, that I'm always so ready for you… not like those girls who are too scared to spread their legs…"

"Keep talking like that, Bella, and I won't be able to last long enough to give it to you…"

"Yes you will… I have… no doubt…" Bellatrix pushed her other foot, the one that had been resting just on the toe on the ground, up and wrapped her legs around Rodolphus's waist, eliciting a moan from him. "Oh, you like that?" she breathed. "You like having me wrapped around you, knowing I'm not going to be able to resist you, knowing you can have me any way you want and I wouldn't be able to say no to you… you love having me around you like this, don't you, Roddy?"

"Yes," he murmured, and then, as Rabastan watched, he shoved her off the wall and let her tumble down onto the desk. Her skirt – a short, charcoal grey, pleated one – went up around her hips and as she lifted her legs, Rabastan caught sight of a slight, black lace g-string.

He couldn't help it. He was undoing the buttons to his trousers before he even knew it, and he was clutching his penis through his boxers, letting out a tiny moan as he stared at Rodolphus and Bellatrix.

Rodolphus grabbed onto Bellatrix's knickers and pulled them off her, letting her kick them to the floor, then lifting her legs and hooking her ankles around his shoulders. "Come on, Roddy… I want it hard…"

Rodolphus was already fumbling at the fastenings to his trousers, and Rabastan stared at his brother's cock when it was freed of the confines of his boxers. He was vaguely aware that he shouldn't be staring at it, he should be staring at Bellatrix, but Rodolphus was so… so…

Big.

A part of Rabastan's mind – a strange, detached part, obviously not as interested as it should be in the mostly-naked Bellatrix lying on the desk, wondered what it would be like to be there, part of that – not in Rodolphus's place, but in Bellatrix's. What would it be like for him to lie on the desk with his ankles around his brother's neck and his hips bucking in the air, waiting to be penetrated?

He shuddered a little. Don't think about that. It's wrong.

"Ooh, oh Rod," Bellatrix panted. "You're… enormous… and so hard, I'll bet…" She reached out and grabbed Rodolphus's cock. "Put it in me, Roddy… I can take it, I want it…"

Rabastan had a perfect view of Bellatrix's flushed cunt as her legs fell open and she spread herself for Rodolphus. It looked so warm, wet and sweet and he wanted to touch it…

Almost as much as he wanted to touch the hard shaft now playing at it. Rabastan's hand tightened around his own erection, pulling at it.

"No more foreplay," Bellatrix breathed, sweat covering her face. "I can't take it anymore. I need… you now…"

Rodolphus gripped her hips in both his strong hands, the tip of his cock pressed against her opening. "Are you ready for it, Bellatrix?"

"Yes!"

He let out a groan, and thrust inside, hard, causing Bellatrix to yelp. Rabastan couldn't even begin to imagine what the couple were experiencing. Well, that wasn't true – he had some idea what Rodolphus must be feeling – he had been with girls before, of course. But, infuriatingly, he found himself more curious about Bellatrix. What did it feel like to be filled up like that? Did it feel good? It must. Did it hurt? Surely it did…

Rabastan sank down on the ground, still peering through the crack between the door and the frame, though he had to tilt his head up at a rather uncomfortable angle to see them. It didn't matter though, because he wanted to see what it would feel like…

He was tugging hard on his penis with his left hand, which felt amazing as it was, but as he kept his eyes fixed on the couple on the desk, he tilted his hips back and slid his right hand into his trousers as well, squeezing his balls lightly, then moving on, pushing his hand deeper inside his trousers, until his fingers brushed against a tight, sensitive opening.

Rabastan was not used to exploring his body this way. He had been told for long enough that masturbation was evil, and he felt guilty enough after a regular, uninteresting session of self-pleasure, never mind anything like this.

He stroked the puckered hole with gentle fingers, pulling on his cock and teasing the foreskin with the other hand. He had never thought skin could be so sensitive…

"Do you think you can make me come?" Bellatrix panted from inside the room. "Do you think you can? Do you think you're man enough for that, Roddy?"

"I know I am," Rodolphus snarled, and Bellatrix issued a high-pitched little squeal. Rabastan felt a wave of complete jealousy, and he jammed a finger inside his ass.

It felt… strange.

Very strange.

Tickly and trembling and hot and tight. And his finger gave him a sense of… of fullness he had never experienced before.

He moved it slightly, and moaned, at the exact moment that Bellatrix did. He looked up at her and saw her clinging to Rodolphus with one hand, the other vigorously at work rubbing herself.

Rabastan, without even realizing what he was doing, found himself mimicking her position. He lay on his back, peering through the crack of the door with his eyes fixed on his brother and on Bellatrix, and pressed his finger in and out of his asshole, all the while vigorously massaging his cock.

Oh God it felt good. Rabastan couldn't hold back moans. His eyes were fixed on the couple, on Rodolphus's long, hard cock sliding in and out of Bellatrix.

"I'm- close!" Bellatrix gasped, writhing, and Rabastan increased his speed.

Bellatrix's back arched and she let out a wild cry of delight. Her legs jerked and she thrashed wildly against Rodolphus, shrieking out his name. And at that very moment, Rabastan, one finger inside his own ass, his hand wrapped tight around his cock, lost control. His seed spurted out of him, coating his hand and his lower stomach, and he fell back, gasping for air. His legs twitched and trembled in the very same way Bellatrix's were as Rodolphus let out a groan and his face contorted with pleasure.

Oh God.

Rabastan's legs were as weak as water as he dragged himself to his feet and stumbled back, away from the room, barely managing to get back to his dormitory. He fell into bed, shaking. Stunned by what he had witnessed. Stunned by his reaction to it.

Stunned by the fact that he had found himself wishing to feel what Bellatrix was feeling.

No. He hadn't wanted to feel like that. Because if he had… that would have meant he was lusting after his own brother. And he wasn't. He lusted after Bellatrix. Simple.

Not so simple as he would have liked.

)O(

Rabastan managed to put thoughts of Bellatrix out of his head for the most part. Despite the fact that Rodolphus took every opportunity to remind him that he was dating Bellatrix Black, Rabastan kept himself busy with his studies, and with a whole slough of girls, none of which were even half as pretty as Bellatrix, and none of which he could manage to come for without thinking of what he had seen in the classroom between Bellatrix and Rodolphus. And as time went on, he managed to convince himself that whatever he had felt – the incredible lust, and the strange and obscene wish to know what it felt like to be Bellatrix and be the one taking it – was simply the product of lack of sleep and – perhaps – some bad food.

And he would have been able to forget the whole matter completely, he had no doubt, had Rodolphus not decided to bring Bellatrix home for the winter holidays.

Rabastan never knew how his parents – let alone the Blacks – let themselves be convinced that that was a good idea. Rabastan could only assume that his parents – woefully oblivious to anything that happened in their own home – thought that Bellatrix was only there during the days, and the Blacks thought that she was being properly chaperoned. Of course, neither were true, which meant that Rabastan was treated to night after night of hearing Bellatrix and Rodolphus in the next room.

It was enough to make him quite sick with jealousy.

Rabastan lay in bed, tossing and turning, trying not to listen to the moans coming from his brother's bedroom. Perhaps, he thought, hearing a long, feminine moan and his brother's distinctive gasping for breath through the walls, the only reason he lusted after Bellatrix was sheer jealousy. If Bellatrix was not so willing with Rodolphus, Rabastan suspected he would have felt no more than a passing fancy for the woman – the same passing fancy that any man to see her felt.

As it was, he would have killed to make her his own.

His memories of her, of how she had looked spread out on that desk, probably didn't help to dispel his fancy for her either.

"Oh, Rod…" came Bellatrix's voice through the wall. "Oh yes…" and Rodolphus was muttering something Rabastan couldn't make out, but that caused Bellatrix to let out a delighted laugh.

This was utterly nauseating.

Rodolphus had had dozens of girlfriends before, of course – no surprise, given that he was handsome, rich and Pureblood, which seemed to be the three criteria that any girl judged based on – and Rabastan had despised every one of them. Stupid sluts, spreading their legs for Rodolphus because they thought they were too good for the younger Lestrange.

Not that he hadn't had his fair share. They were all better than Rodolphus's girls – at least, any of Rodolphus's girls besides Bellatrix – Rabastan thought, but none of them had been good enough for him. He had kept them more to spite his brother than anything else, and bragged about the things they would do for him.

A shriek of delight pierced the air, and Rabastan winced. Bellatrix was no better – the whore, screaming like that for his brother. They weren't even discussing, and yet she behaved as though there was no shame at all in sleeping in Rodolphus's chambers, and waking up Rabastan with her overloud proclamations of pleasure. It had been one thing to fuck him in the dead of night in an empty classroom, but this… this was simply obscene.

Rabastan covered his face with a pillow, but the noises from the adjoining room were far too loud for the delicate feathered thing to block out.

"Oh Rod, just there, yes! Oh, oh, harder! Go- harder!"

Of course the slut would want it hard. Rabastan snorted derisively to himself. She probably loved getting fucked like the whore she was, hot and dirty.

Another cry of pleasure, and Rabastan had had enough. He turned on his lights, cast a silencing spell over the room so he couldn't hear them anymore, and grabbed a book to read.

Ah, he thought, leaning back and opening the book. The quiet is so relaxing…

In the quiet, it was easy not to picture what Rodolphus was doing to Bellatrix, which was a mercy. Rabastan quickly became engrossed in his book. He was completely lost in a world of medieval political intrigue when the door opened.

He looked up, quite surprised at the soft noise of the hinge creaking open, and his face flushed crimson when he saw Bellatrix in the doorway. She was sweaty and flushed, hair dishevelled, dress pulled on haphazardly.

"What?" Rabastan asked, glaring at her. She scarcely ever talked to him, and he hated it when she did, because of the ways he patronized him and acted as though he was inferior to his brother, a sentiment Rabastan despised – though, to a degree, he knew perfectly well that it was true. If he weren't inferior, then Bellatrix would be with him.

"I wanted to apologize," Bellatrix purred, "for the noise… Rodolphus and I must have been disturbing you…"

"Yes, you were rather. Would you mind leaving?" he asked curtly. Much as he lusted after her, he didn't fancy having his brother's sloppy seconds.

Bellatrix ran her hand through her already wild hair. "But Rab…" she murmured, in the softest, most velvety, most seductive voice that Rabastan had ever heard, "Rodolphus was such a disappointment… and I'm sure you wouldn't deny a lady…"

"What are you on about?" Rabastan's voice was purposefully icy.

She was drifting over to his bed now, slow and almost dreamy. "He got me… all wound up… and he didn't finish me off…" she breathed.

Rabastan swallowed hard.

She leaned forward, her hand moving out to touch his cheek. "But you… I'll bet that you know how to please a woman… I'll bet you're much better at it than Rodolphus…" Her hand was skating down his throat now, coming to rest on his bare chest.

"I don't think–" he began, but Bellatrix rested a finger against his lips, shaking her head. Her other hand was down at the waistband of his pyjama trousers now, skilfully undoing the buttons. Rabastan's breath caught as her cool, slim fingers wrapped around him.

"Oh," she breathed, freeing his penis and giving it a few leisurely strokes. "You're so big…"

Rabastan twitched. He was hardening quickly under her hand, and trembling from sheer disbelief. Was he dreaming?

Her warm lips pressed against his, and he no longer cared. If this was a dream, he was not interested in waking up.

Bellatrix was pressing him back onto the bed now, yanking at her clothing, smearing kisses against his mouth. His hand was around his erection, massaging it as she moaned quietly against his lips. Rabastan fell back against the pillows, unsure what to make of this but not caring. As Bellatrix pulled off her dress, he thought she looked every bit as gorgeous stark naked as he thought she would.

"Oh… Rab…" she purred when she slid his trousers down and her bare body pressed against his.

"What the hell is going on in here and why wasn't I invited?"

Rabastan's eyes, which had been almost shut as he enjoyed Bellatrix, snapped open and he jolted upright at his brother's voice. Rodolphus, in only a pair of hastily-yanked-on trousers, was leaning against the doorway, scowling at his brother and at Bellatrix.

"I–" Rabastan began, but Bellatrix cut across him smoothly.

"Why don't you join us, Rod?"

Rodolphus raised an eyebrow. "I don't much fancy sharing my girlfriend with my brother," he said icily.

Neither do I, Rabastan thought, but he said nothing.

"Sharing is caring, Roddy," Bellatrix said, in a horrible sing-song voice. Then, reverting to her normal tone, "Either learn to share me or you won't get me at all, Rod. Understood?"

Rodolphus grimaced, looking like he wanted very much to leave, but when Bellatrix bent to press another deep kiss to Rabastan's lips, a smile broke across his face. Rabastan's breath caught as his brother joined them on the bed, his hands rubbing up Bellatrix's waist as he knelt beside her.

Bellatrix twisted and kissed her boyfriend's lips, though her hands were at Rabastan's crotch, massaging his cock until it was completely hard. Rodolphus fumbled with the fastenings of his own trousers, and, without thinking, Rabastan reached out and undid the buttons, freeing his brother from the fabric confines. As he pulled back, his finger's brushed Rodolphus's shaft, and he felt a blush rise in his cheeks.

Neither Rodolphus nor Bellatrix seemed to have noticed anything. Bellatrix was shifting into position, hovering over Rabastan, and she slowly – oh, so wonderfully, deliciously slowly, sank down on him. Rabastan moaned, and his moan increased in volume when Bellatrix leaned forward, reaching behind herself and spreading her ass wide for Rodolphus. Rabastan watched, aroused more by the sight of his brother slowly sliding into Bellatrix than by the heat and wetness of her body around him.

Bellatrix moaned, her face contorting with pleasure, as Rodolphus's cock sank into her tight body. Rabastan could have sworn he felt something, a pressure on his cock as though with Rodolphus in her as well, Bellatrix's body was pressing them both tighter. He moaned, and though Bellatrix in between them was writhing and moaning and smearing kisses on him and on Rodolphus, Rabastan found himself watching his brother with fascination – the expression of concentration as he thrust inside Bellatrix, and the pleasure that danced in his eyes with every move she made.

Bellatrix was not concentrating, but she certainly seemed to be experiencing a great deal of pleasure. She writhed in between them, and her moans escalated in volume. Her excitement was catching, and it wasn't long before both men were moving with just as much enthusiasm as her.

She let out a wild cry, and Rodolphus felt her body tighten – go tighter than he had ever imagined a woman's body could go. He too could feel an orgasm building in his stomach, and judging by Rodolphus's passionate moans, he could as well.

As Bellatrix tossed her head, Rabastan blinded by her hair. He wasn't even the slightest bit aware of what he was doing – his impending orgasm had him delirious, her movements had him disoriented, and he reached out, pulled his brother down to him, and kissed him deeply. It was at that precise moment that he let go, and as he kissed Rodolphus, he came hard, filling Bellatrix with seed, and he could tell by the way Rodolphus was shaking that he was doing the very same thing.

At last, all three lay still, and Rodolphus felt his stomach twist in intense guilt. He immediately broke away from his brother, looking away.

Bellatrix, sandwiched in between the men, snorted.

"I don't believe this," she snapped, pulling herself out and glaring at both of them. "I give you two the times of your life, and this is how you thank me? By kissing each other instead of me? Well, maybe some girls like that sort of thing, but- eugh!" She grabbed her dress and pulled it on, storming out of the room, leaving the brothers entangled on the bed, stunned.

Rabastan's mind was racing. He had kissed another man – his brother of all people. And he had… had…

Had liked it.

He had liked it far more than kissing any girl.

Rodolphus stared at him for a moment, warily, then shook himself. "Fuck," he muttered, and stood up grabbing his trousers and yanking them back on to follow Bellatrix.

That left Rabastan sprawled in bed, stunned.

If he liked kissing Rodolphus…

If he fantasized about taking it the way a girl would…

Did that mean he was…

He couldn't even think the word.

Did that mean he… "preferred the company of men"?

He didn't know, not really. He was so used to liking women, anything else seemed strange to even begin to contemplate, but… but…

Whether Rabastan was… whether he preferred men or not, there was one thing he was completely sure of. Thinking back, he had been sure of it for a long time – at least since that time he had watched Bellatrix and Rodolphus together, and probably since long before that – but he had never been able to admit it even to himself. The kiss had simply sealed the matter, made it concrete and definite.

Rabastan Lestrange was hopelessly, desperately in love with his brother.

He simply couldn't help it.

)O(

Fin