Finn smiled at the shocked faces in front of him. He'd hated the Melbourne twins for as long as he could remember, and now he finally had a chance to get even.
He pointed to his smartphone screen for emphasis, as if they didn't already know he had just snapped a picture of them making out.
"Man, I wonder what your parents will think of this? Good little brothers and sisters don't make out with each other, you know."
Ben and Nadia glared at him, their fine-featured faces wearing matched expressions of hate.
"What do you want, fucker?" Nadia's blue eyes flashed, and she tossed her golden hair contemptuously.
An idea hit Finn suddenly, and he grinned broadly as he ran a hand through his own dark hair.
"I haven't had a good lay in forever. Since you two horndogs are clearly in the mood anyway, let's make it a threesome!" His eyes glinted wickedly. "If you satisfy me, I won't show this lovely family photo to your mom and pop."
Ben started to stand, his hands balled into fists. "You son of a bitch!" he snarled. "You think you can blackmail us?" But Nadia laid a delicate hand on his chest, holding him back. Ben was no wimp, but Finn had a reputation as the dirtiest fighter at school.
"If we do this, you have to let us delete the picture so you can't blackmail us again," she said. Finn smiled, noting to himself that she was the cleverer of the siblings.
"Deal," he said.
One short, tense car ride later, they were at Finn's place. He took advantage of the twins' distraction as they checked out his place, and quickly texted the photo to his email for safekeeping.
"Enter, please, my friends!" He swept the door open, and ushered them in.
A short time later, they were naked in his room, Nadia sucking his cock and looking up at him with those electric blue eyes of hers. He moaned and thrust his hips, enjoying the sight of the school's rich princess on her knees serving him.
"Oh, that's good," he moaned. "Bet you've had a lot of practice on your brother, hmm?" Nadia's eyes darkened, but she said nothing, and Ben avoided his gaze. Finn just smiled and twined his fingers through Nadia's hair as he started fucking her throat.
She gagged and tried to push him away, but he just thrust deeper, sighing happily as her tight throat opened to take him all the way down. When his balls started to tighten, he let her go.
"You bastard!" she wiped her mouth angrily. "What did you do that for? I could barely breathe!"
In response, he pulled her to her feet and kissed her hard, until she moaned into his mouth.
"Doesn't seem like you're really all that angry," he smirked. She stuck her tongue out at him, half annoyed and half playful.
Ben had been doing his best to ignore them, but Finn could see that his cock was getting hard despite that.
"Hey, Prince Charming, take a turn in your sister's mouth while I fuck her pussy," he said, reaching over to smack Ben's ass.
The sandy-haired boy waved Finn's hand away, but positioned himself in front of Nadia's mouth anyway, and she slurped him down hungrily. Before long, Ben was fucking her mouth just like Finn had.
Meanwhile, Finn moved behind her and slid a fingertip along her already-wet slit.
"You're enjoying this, you little cocksucker!" He slid his finger deep inside her, making her moan. After finger-fucking her to get her ready, Finn slid his hard dick into her pussy in one motion, making her moan and arch her back. He slid in and out, moaning at her heat and tightness, and growing harder when he saw how every thrust pushed her nose against Ben's pubes and made her gag.
He slid a hand to tease her clit as he fucked her, and smiled as Ben started tweaking her nipples, making her squirm like a bitch in heat. He smacked her ass and thrust into her hard, loving how her cunt squeezed his cock when he pounded her.
After a while he started fucking her slower, so as not to cum just yet. Her legs were already trembling, and her eyes were watering from deepthroating her brother, but he still had more in mind for her. While he fucked her with long, deep strokes, his thumb slipped to her asshole and started making gentle circles. Nadia gurgled in protest and tried to shift away, and the boys' eyes met in understanding.
"I've never fucked her there," Ben said, but made no move to stop Finn's exploration.
Her tight sphincter slowly gave way as he pushed his thumb deeper, and she moaned. Finn pointed to a bottle of lube on the nightstand, and Ben stopped fucking his sister's mouth long enough to retrieve it. Nadia gasped and tried to squirm away, but Finn held her close.
"Please, not there!" she begged. "You're too big for my ass, and you've already fucked me so hard I can barely stand!"
Finn stroked her back and buttocks soothingly, leaning over her to whisper in her ear.
"I'm going to fuck this tight ass," he told her. "But if you push out like a good little girl, it will hurt less."
She whimpered in nervous submission as he pushed his finger deeper, letting his cock slip out of her pussy in preparation for her ass-fucking. She looked to her brother for comfort, and he stroked her cheek as he handed Finn the lube.
"It'll be okay, sis," he said. "Besides, I've always said you have a hot ass!" She glared at him and moaned as Finn's now-lubed cockhead pushed at her tight rosebud. She gasped as he pushed past the resistance, deeper into her ass, and she clutched at her brother desperately as her legs started quivering uncontrollably.
Unexpectedly, Ben grabbed her head and started fucking her throat again, muffling her screams as Finn fucked her deep in the ass.
Finn moaned deep in his throat. He was fucking a hot, stuck-up blonde girl in her ass while she gagged on her brothers cock. This must be what heaven was like, he thought.
Before long, Ben exploded in his sister's mouth with a groan of pleasure. She slurped the hot cum up greedily, swallowing as if by reflex, and licking her lips to get the little dribbles that escaped her mouth. Ben sighed happily and began to massage her sides and back, helping her relax for the rough ass-fucking she was enduring.
Finn could tell she was starting to enjoy it, though, as she lifted her hips up to meet his thrusts. When she started wiggling her ass in little circles, begging for more, he spanked her and fucked her harder. That drew a reaction immediately.
"Oh, yes!" she screamed. "Ream my little ass, you bastard! Fuck me like an ass-slut!"
Finn was tempted to empty his balls into her butt, but he still had one more thing planned, so he pulled out, causing Nadia to moan in distress.
"Put it back," she pleaded. "I want to feel you cum in my ass."
"Maybe later," he replied. "For now, that will be your brother's pleasure."
Once again, he enjoyed their shocked looks. Ben predictably started to protest.
"No way, man!" he said quickly, backing away from Finn a few steps. "I don't swing that way."
But Nadia stepped in at this point, marching up to her brother and grabbing him by the cock.
"Listen here, mister," she said. "You let me get fucked in my ass, so you can take the same, or I'll show Mom and Dad the picture myself!"
With that, she pushed him onto Finn's bed and forced him to get on all fours, stroking his cock all the while.
With a grin, she grabbed the lube and spread his butt cheeks wide, exposing the tight hole. Looking Finn right in the eyes, she slowly slide a lubed-up finger deep into her brother's asshole, making him moan uncomfortably.
"C'mon, big boy," she said to Finn. "Come make my brother your bitch just like you did to me."
Finn pressed his rock-hard cock against Ben's asshole, enjoying how he clutched the sheets and wiggled his ass nervously, and how his sister pinned him to the bed with her body weight and spread his butt cheeks to help him get fucked.
When his cock slipped past the resistance into the other boy's ass, Finn moaned deeply. Nadia moaned too, slapping her brother's ass hard. Ben groaned and whimpered quietly, trying not to cry out.
That resolve broke down quickly as Finn started to fuck him pumping his cock in and out slowly, going balls-deep each time. Ben made a noise that was halfway between a moan and a scream, but Nadia still held him down, reaching between his legs to play with his cock.
Finn looked deep into her eyes while he fucked her brother, loving the evil spark he saw in those blue orbs. She moved to kiss him suddenly, and he was surprised by the passion.
"Fuck my brother hard, stud," she said. "It makes me so hard to watch him taking your cock in his ass!"
She kissed him deeper, sliding her tongue against his, and he erupted into Ben's ass, moaning loudly into Nadia's mouth as he came. She continued playing with her brother's cock and balls at the same time, until he too exploded in a hot, sticky mess.
She tossed her hair and smiled wickedly as she licked her brother's cum off her hand, then leaned down to clean Finn's cock as it slipped out of Ben's well-fucked ass.
Ben crawled off the bed sheepishly, carefully avoiding eye contact with either of his partners. Finn smiled and sighed contentedly as Nadia finished cleaning his cock, then laid her head on his chest.
Later, after the twins went home, Finn fired up his computer and checked his email. Noting that the twincest picture was safe and sound, he began dreaming up other ways he could blackmail the siblings. Though given the way Nadia at least had reacted, he thought, blackmail might not be required.
Finn and Nadia became college sweethearts, and married soon after graduation. Every now and then, Ben visits -- Nadia jokes that he comes for Finn's cock in his ass. He always protests, but sooner or later, the three end up in the bedroom, and his ass always ends up well-fucked.