Jase and his older sister Mia had always had a complicated relationship. As the younger brother, Jase had grown accustomed to being teased, bossed around, and generally mistreated by his bratty sibling throughout their childhood and teen years.
But this past summer, their parents had surprised Jase with the exciting news that Mia would be leaving for college and he was allowed to take over her spacious bedroom. Mia had always been very possessive of her room and Jase had never been allowed to enter unless explicitly invited. So this was a huge upgrade for the 14-year-old boy.
Jase eagerly moved his belongings into the newly vacated space, relishing in his privacy and the distance from his annoying older sister. For a blissful few weeks, he had the run of Mia's room - the plush queen-sized bed, the convertible futon, and most importantly, the complete lack of Mia's constant presence.
But those halcyon days of freedom were short-lived. Mia abruptly returned from college one weekend, moving her suitcases and belongings back into the house. Jase's heart sank as he realized he would now have to relinquish his adopted bedroom.
Upon learning of the sleeping arrangement, Mia was livid - absolutely outraged that she was being relegated to the lumpy living room sofa while her younger brother lounged comfortably in her bed. She loudly berated their parents and Jase, who meekly tried to appease her. Sleep that night was difficult, punctuated by angry huffs and loud sighs from the living room.
Jase drifted off that evening, feeling guilty but also self-righteous about his new sleeping setup. But in the dead of night, he was shocked awake by Mia barging into his room.
"It's freezing out there! And the couch is SO uncomfortable," she grumbled, her bare legs sticking out from under a loose shirt. "I'm sleeping in here. Move over!"
Jase's eyes widened in disbelief at her brazen entrance. Mia was wearing nothing but skimpy panties and a thin camisole top. He could plainly see the outline of her pert nipples and the curves of her round butt cheeks.
"No way, you were so mean to me! I'm not gonna let you kick me out of MY room now," Jase protested weakly, trying to hide his morning wood.
Mia scoffed and clambered into the spacious bed beside him anyway. "I don't care. Just stay on your side, dweeb."
Jase rolled over, not wanting to risk any more of an argument, especially with his dick straining in his perma-soaked boxers. He tried to ignore Mia's proximity, the intoxicating smell of her night cream and the way her supple body already felt so close to his own.
But Mia wasn't having it. She continued to complain about the cold, shivering dramatically. "Jace, you're like an iceberg! It's freezing over there!"
"Deal with it. I'm not moving any closer to you," Jase grumbled.
"Ugh, fine. Then just hold me so I don't freeze my butt off," Mia demanded imperiously, yanking his arm over her shoulder.
"Mia! Stop, you're totally gonna get me hard," Jase whined. But she just smirked and wiggled her ass back against him, rubbing her panty-covered cheeks right on his crotch.
"Oooh, looks like someone IS getting hard!" she cooed in a mocking singsong voice. Mia reached back to feel his stiffening member. "Seriously, it's like a little baseball bat in my hand!"
Jase bucked his hips, both trying to avoid her grip while chasing more of that delicious friction on his throbbing cock. "Don't touch it, you perv! I'm just gonna wank it out real quick. Go back to sleep."
But Mia wasn't about to let her little brother get off that easy. "Oooh, you're so horny! Want a hand with that?" she purred, circling her fingers around his shaft through his boxers.
"N-no, I can do it myself!" Jase stammered, even as he continued bucking into her grip. Mia just grinned wickedly and tugged his underwear down, freeing his achingly stiff cock.
She pumped his hot hard rod in her fist, her fingers barely able to encircle his girth. "Holy crap Jace, you're pretty hung for a 14-year-old. I bet the girls just love this thing!"
Jase could only groan, his hips stuttering as Mia worked his cock with devastating expertise. He knew he shouldn't be letting his own sister jerk him off like this...but it just felt too damn good!
Mia could see he was close. She released his cock and used both hands to pull her skimpy panties to the side, revealing the glistening pink folds of her virgin pussy. "Jace, fuck me. I need that big cock inside me!"
In a lustful daze, Jase let Mia guide him on top of her. He rubbed his cockhead through her soaked slit, both terrified and excited to pop her cherry.
Mia locked her legs around his waist, pulling him closer. "Come on, just slide it in! I'm on birth control," she whispered urgently, her nails digging into his back.
With a rush of courage, Jase pushed forward, feeling his engorged head pop through her impossibly tight hymen. Mia gasped and Jase froze, both siblings panting at the slight burn.
After a moment, Mia started moving her hips, urging him to fuck her deeper. "Come on Jace, you feel amazing! Pound me with that fat cock!"
And Jase let himself fully surrender to the pleasure. He started pumping his hips, driving into Mia's impossibly tight cunt with shallow thrusts.
Mia whimpered and mewled, her pussy clenching greedily around his pistoning shaft. "Harder Jace! Yes, yes, yes!"
Their coupling quickly escalated, the siblings losing themselves to the forbidden bliss. Worrying thoughts were pushed aside as they rutted together like animals in heat, the wet slick sounds of their fucking filling the room.
"Hnnggg...I'm gonna...gonna...cum!" Mia wailed, her nails raking down Jace's back as she bucked under him wildly.
"Me too sis! Gonna cum in you!" Jase grunted, pistoning into her quivering cunt like a jackrabbit.
With a chorus of strangled moans, sibling orgasmed together, their virgin couplings complete. Jace shot spurt after spurt of his potent seed deep into Mia's fertile womb. Mia's pussy spasmed and milked him for every drop.
After long, blissful minutes, they collapsed into a sweaty tangle of limbs. Jace's cock slipped out of Mia's pussy with a gush of combined fluids.
The siblings lay there in the afterglow, both dazed by what they had just done. But beneath the shock and shame, a new dark desire had been kindled between brother and sister. A desire that would change their relationship forever.