Story title:Weakness
Pairing(s):Kinn (Kurt Hummel/Finn Hudson)
Warnings:Age difference, infedelity, pseudo-incest(step-siblings)
Word Count:3198
Other Notes:My beta is lovely. I would tell you to check out her fic, but she doesn't write any, ahaha. Regardless, all mistakes are my own.

Fill for a prompt on the GKM: Finn is older than Kurt and home from college for the holidays. He wants Kurt, but Kurt is underage and inexperienced, not to mention his stepbrother. One night when they're watching a scary movie marathon, Burt and Carole go to bed, and Finn seizes the opportunity. He pretends to fall asleep and that he's having dream!sex. He slips his hand into Kurt's pants, giving him a handjob and then falling into Kurt's lap to suck his dick. Kurt tries pushing him off at first, but then he enjoys it too much. He ends up riding Finn's cock while Finn still pretends to be sleeping.

I deviated a bit, but I hope the OP enjoys anyway. (:

Kurt Hummel was attractive. Long legs and alabaster skin and clear blue eyes with the tightest ass Finn had ever seen. And he also happened to be the son of his mother's husband, not to mention only sixteen years old. Usually, Finn didn't interact with Kurt much. By the time Carole and Burt had gotten married, Finn was already twenty-one years old and in his junior year of college. He was majoring in advertising, and his mom was real proud of him for getting out of Lima, despite his less than stellar grades. Kurt was everything that Finn Hudson was not: stylish, haughty, out and proud. He ate well, did Pilates, and read iVogue/i with the intensity of a man watching lesbian porn. And yeah, Finn could appreciate a tight ass on a hot guy, but he wasn't wearing rainbow flags and screaming his bisexuality like Kurt screamed his homosexuality.

Though, to be fair, Kurt couldn't really help it. His voice was high and beautiful, and he preferred singing and fashion and show choir and theatre to football or sweating it out in a gym or watching action flicks. It made blending in with the other guys a little hard when he wore Alexander McKing sweaters to school and sniffed in disdain at one of the jocks' polos. Finn found his courage admirable. A little foolish, perhaps, but admirable. Finn was a legend at McKinley, which gave Kurt a bit of leeway – not to mention the terror that Burt Hummel's mere presence seemed to inspire. Finn Hudson had won the state championship title for McKinley's football team two years in a row, and been quarterback for three.

Kurt didn't mention his relation to Finn very often, though, or so he gathered from his friend Puck's little brother. Noah Puckerman had dropped out of McKinley when he failed senior year, and he'd tagged along with Finn to crash at his place when he'd gotten his scholarship to Ohio State. Puck contributed to rent by tending bar and flirting with anything that walked, and he made more in tips than anyone else in the place due to his charismatic nature. Unfortunately, it was now summer break, and Kurt had neglected to take any summer classes as he had the past two years. The boy was sixteen and beautiful, tall and lean and gorgeous. And god, did Finn want him.

Since it was summer, Kurt sent his layers to the back of his closet and brought out his tanks and shorts. It drove Finn crazy, watching him parade around in tight shorts and breezy tanks that hinted at the pinkness of his nipples through the thinness of the material. Finn found himself watching Kurt all the time, eyes tracking the planes of his pale body. He got a few strange looks from the younger boy, but other than that, Kurt didn't seem to notice the sudden attention, for which Finn was grateful.

The first time Kurt called him out on anything, they were at the house of one of Kurt's friends. Rachel Berry was obnoxious and self-centered and the female counterpart to Kurt's haughty, cool behavior – though Finn wouldn't dare to tell him that to his face. Finn was in the pool with his Puck and Puck's little brother Ethan, who happened to be Kurt's age. Kurt's other friends were at the shallow end, dipping their toes in and talking and laughing. Puck and Finn were dunking each other and ganging up on Ethan, who was on the swim team and kind of kicking their asses, so to speak.

Finn shook the water off of himself, getting out of the pool and heading over to Kurt, who sat with his sunglasses and a bottle of sunscreen. He was trying to reach the glob he'd smeared on his freckled back, with no success. Finn found it sort of adorable, how his nose would scrunch up and the sunglasses perched precariously on the top of his unstyled hair would wobble and let another piece fall into his eyes.

"Need some help?" Finn asked after a moment, drying off forgotten as he thought about rubbing white, creamy substance into Kurt's creamy skin.

"Uh..yes, please," his stepbrother answered, voice young and embarrassed and cheeks flushed. Finn wondered if it was from the sun or embarrassment. He found he liked Kurt all red and flushed. He took the bottle of sunscreen from Kurt's hand and instructed him to turn around. Finn smoothed his large, calloused hands down the expanse of Kurt's pale, freckled back, pleased at the small shiver that worked its way down his spine. He was methodical, spreading the sunscreen into the boy's skin and rubbing gently as he did so. They passed the time silent, nothing but the sound of their breathing in their little bubble.

He spent extra time making sure that the sunscreen was massaged in on Kurt's lower back, thumbs teasing the waistband of his swim trunks. Kurt pulled away soon after, and Finn hid his disappointment by offering a goofy grin.

"There ya go, bud. Just figured you could use a hand. I'm out." He went back to the pool and used the cold water to cool himself off. His stepbrother was far too attractive for his own good.

When they got home, they were both exhausted, but Finn convinced Kurt to curl up with him on the couch and watch a movie. He'd even been allowed to choose, so he knew Kurt must've been tired. Normally they fought for at least an hour about what to watch and got so frustrated that they didn't watch anything. He chose Texas Chainsaw Massacre, despite knowing how Kurt reacted to scary movies. They'd parted ways to change, and when they reunited, Finn wore a pair of old, ratty sweatpants and no shirt while Kurt chose a pair of black yoga pants that hugged his ass and hips and a plain white t-shirt.

Kurt took a blanket from the back of the couch and wrapped it around himself, taking his seat next to Finn with a decent amount of space between them on the couch. Displeased, Finn pressed play. Within ten minutes, Kurt was pressed against him, sharing his blanket and peeking over it, wide blue eyes fixed on the screen. By the middle of the movie, Finn was half-asleep, head lolling and body lax. Kurt, however, was wide awake, biting his lip and huddling under the blankets, shooting up at every creek in the house. He cursed the fact that their parents had gone out on a date and wouldn't be home until around two in the morning. Their dates always ran late.

"Finn," Kurt hissed, poking him sharply. He ignored the smaller boy, making a sleepy noise and turning his head the other way. "Finn Hudson, wake up!" Finn suddenly got an idea. He'd heard of people doing sexual stuff in their sleep, like jerking someone off. Maybe this was his chance. He decided to be careful at first, just to see how Kurt would react. He trailed his big hand up Kurt's thigh, stroking it softly. Kurt gasped, fixing his gaze at the TV and biting his lip.

"Finn," he said, voice more frantic. "Are you awake?" Instead of answering, Finn moved his hand and slipped it down the yoga pants and inside Kurt's briefs to wrap around the boy's semi-hard cock. Oh, to be sixteen again, he thought idly as he stroked Kurt gently, grip loose and teasing.

"Oh," Kurt said stupidly, hips bucking of their own accord. "Oh, Finn, that feels…" He trailed off when Finn's grip tightened and he added a twist at the head as he came up, grip sure and firm and Kurt gasped and bucked up into the touch, mouth open. Finn watched him through slitted eyes as he writhed on the couch, enjoying every tremor he pulled from the smaller boy's body. He wanted to fuck this beautiful boy, he realized, age restrictions and family ties be damned; he wanted to be inside Kurt's clenching hole more than anything.

He dragged his hand from Kurt's cock, ignoring the whine of disappointment, and trailed it down to the little furl of muscle nestled between his firm, pale cheeks. He pressed dry fingers against the muscle firmly, rubbing it gently and teasingly as Kurt whined in surprise. The smaller boy shifted uncomfortably, face flushed.

"Uh, Finn...if you, uh…I have lube. I mean – I can…in my room." Finn withdrew his hand and allowed Kurt to go, watching his ass sway and frowning when the boy came back with a half-empty bottle. He took it from Kurt and made Kurt shuck off his pants and underwear, spreading his thighs and slicking his fingers and sliding one inside, ignoring Kurt's surprised moan as he crooked it and found the bundle of nerves inside. Finn's longer fingers allowed him to easily massage and tease it until Kurt was practically crying, begging for more. Still half-asleep, Finn added another finger.

"Who did you do this with, Kurt? Huh? Who'd you let inside you before you let your big brother touch you?"

Kurt moaned brokenly, thrusting down onto Finn's fingers as he clenched his fingers in the blankets.

"N-no one, Finn, I swear. Just used it on myself, so I'd know what it felt like."

"Did you like it?"

Kurt didn't answer, just wailed when Finn thrust another finger inside and forced all three hard against his prostate.

"I asked you a question, Kurt," he said, tapping the bundle of nerves, stroking it mercilessly.

"Y-yes," Kurt moaned, eyes welling with tears from the stimulation. "I liked it so much, Finn, please."

"Please what, honey? What do you want, Kurt? Go on, tell me, " Finn commanded, scissoring his fingers and working Kurt open.

"Want you inside, Finn, please. Please," he begged shamelessly, thrusting against the feel of Kurt's fingers inside, cock hard and leaking against his pale belly.

Finn didn't respond, just grabbed Kurt by the hips and lifted him easily, sliding him onto his lap and pressing his cock against Kurt's entrance. He held the small boy by the hips, huge hands digging into the fragile skin and sure to leave bruises. As he lowered Kurt down, he groaned at the unbelievable tightness of the boy's body. Kurt strained against his hold, and he gave up trying to hold either of them back, slamming Kurt down the rest of the way onto his cock. Kurt screamed, body tensing and fingernails digging into Finn's shoulders. Finn struggled to breathe through the fog of lust that enveloped him at the feel of Kurt's unbelievable tightness wrapped like hot velvet around him.

"God, Kurt, you feel so good," Finn groaned, leaning his forehead against his younger stepbrother's.

"Finn," the boy whimpered in response, rocking his hips in earnest and crying out when Finn's cock hit his prostate.

He began to ride Finn in earnest, strong thighs lifting himself and dropping himself back down as they both hurtled towards climax. Finn took hold of Kurt's cock, jerking him in time to his rough, hard thrusts. When Kurt came, he was even more beautiful than Finn knew he could be. His full, pink mouth opened in an O, stunned blue eyes unfocused as he flushed from cheeks to chest, body arching in a beautiful bow as his hole rippled and he covered Finn's chest in his come. Finn couldn't resist the feel of Kurt's clenching hole, shooting his load deep inside his stepbrother, come coating Kurt's insides hot and wet.

Kurt slumped against him, sweaty and shaking. "F-Finn?" he asked timidly, after a moment.

"Hm?" Finn answered lazily, already on his way back to sleep.

"Will you, uh…will you kiss me? I've never been kissed before and…well, please?"

Kurt's eyes were so full of hope and fear of rejection that Finn just leaned down and pressed their mouths together without answering. Kurt tasted like sweat and salt and cherry Chapstick, and his lips were full and soft and addicting. When Finn ran his tongue along the seam, Kurt willingly parted his mouth to grant Finn access. Tasting Kurt was like tasting a fine wine: dizzying and perfect.

The kiss was lazy and wet: a slow slide of their tongues together while Kurt acquainted himself with the feel of kissing another boy this way. They pulled away when the need to breathe outweighed the need to keep kissing, and Finn pressed a kiss to Kurt's forehead before lifting him up easily and standing.

"Can't get caught spooning on the couch, little bro," Finn said cheerfully, carrying Kurt downstairs to his room and laying him down on his bed. "Stay here."

Finn left to lock the house up and shut the lights off, returning to Kurt's bed with his boxers on to find the boy fast asleep, fresh pair of briefs and a pair of new pants on. This pair was looser, resting low on the boy's perfect hips. Finn smiled and climbed into bed behind him, spooning up against his back and pulling Kurt to his chest. He fell asleep with a smile on his face and a leg between Kurt's.

The next morning, Finn Hudson awoke to an empty bed and a guilty conscience. He'd taken advantage of his beautiful stepbrother last night, and no matter how much he wanted to ravage Kurt, no matter how he remembered the way Kurt had looked when he had come, it could never happen again. He would have to muster self-control, remember that the boy was only sixteen, was just a child, was his stepbrother. And yet, when he walked upstairs to find Kurt in only his sleep pants, explaining that their parents were running errands all day, he couldn't help but drag the boy into his arms for a kiss, couldn't help but run to get the lube and have Kurt right there up against the counter, his ass perched on the edge while he begged for more, harder Finn, yes, yes, right there ohhhh. And who was he to deny Kurt when the small boy insisted on cuddling downstairs in his room and watching movies all day?

And no, Finn couldn't be blamed for the way he kissed Kurt's mouth, trailed kisses down Kurt's chest, bit at Kurt's nipples. "God, you're beautiful," he groaned, face pressed to Kurt's navel. Kurt's blush was enough to spur Finn on, and once Kurt's pants were gone, he took Kurt in his mouth, suckling on the head of his rosy cock and digging his tongue into the slit while Kurt tried in vain to buck his hips against Finn's unforgiving hands holding his hips to the bed. He pressed his forearm against Kurt's hips to press him down, using one hand to tease his still wet and stretched entrance, sliding one finger inside and rubbing against the bundle of nerves he found there endlessly until Kurt came down his throat. He was a spitter at heart, no matter how he'd accepted his sexuality, and so he found an empty cup to spit Kurt's seed into. He pulled the small boy into a kiss, sharing his taste, and they lay together in bed until their parents came home.

Reality slapped them in the face in August, when Finn had to get ready to leave for his fourth year of college and Kurt had to begin searching for his wardrobe for junior year. They'd spent any and all free time they had locked in Kurt's bedroom. Finn had taught Kurt the art of deepthroating, sang praises to Kurt's nearly non-existent gag reflex and apologized profusely that he didn't share Kurt's abilities at fellatio. Kurt had laughed and insisted Finn fuck him instead.

Kurt modeled his fall fashions for Finn, who mostly commented on how well they accented his various attributes: how they made his eyes pop or his ass look even better than usual. Kurt didn't mind; he knew Finn was simple when it came to fashion, and it was nice to hear he looked good. Finn explained his major to Kurt, and bought all his textbooks. As each one arrived, Kurt felt his heart sink a little more. Finn was really leaving.

On August 18th, Finn and Kurt were alone in the house. Burt and Carole had gone out to catch a movie and they sat in Finn's room among his half-packed boxes. "You're leaving," Kurt said quietly, glancing at him with resignation in his eyes.

"Yeah," Finn agreed, eyes downcast. "I'm leaving, Kurt."

Kurt kept his eyes on the floor, twisting his fingers together.

"I'm sorry, Kurt." Finn didn't know what else to say.

"I know you are. I understand."

And Kurt got up and left the room.

Finn left for his fourth year of college on August 20th. Kurt started his junior year of high school on September 6th, and he did fairly well in his classes. He met a new boy who had transferred from a school in Westerville. His parents had moved to Lima to be closer to their family, and Blaine was sweet. They began to date on October 28th, and when Finn came home for Christmas break, he realized that things would not be as they had before. As naïve as it was, Finn had expected to come home and find that Kurt still wanted him in his bed. Instead, Kurt gushed about a boy named Blaine, about how he was sure he was in love, despite how young he was. And though Finn caught Kurt staring at him with sad eyes sometimes, Kurt never mentioned what had happened between them the previous summer, so Finn didn't either.

When Finn came home for spring break, he brought a girl named Dani that he'd met in one of his classes. Carole loved her immediately, and Kurt learned that they'd been dating for five months. Kurt was happy for Finn. The two co-existed uneasily, their significant others oblivious to the tension that always thickened when they were together in a room. Finn and Dani got married in June. Though Carole worried it was too soon, Finn insisted that Dani was the one he wanted to spend the rest of his life with. Kurt brought Blaine to the wedding and danced with him, ignoring Finn's eyes on his back.

That night, Finn crept into his bed and they fucked again, Kurt crying against Finn's neck as Finn thrust inside of him. "No one can have you like this, Kurt," he begged, fisting his hands in Kurt's hair and dragging his head back for a filthy kiss. "Please. Tell me Blaine hasn't had you like this. You're mine."

When they came, Finn collapsed, sliding out of Kurt and pulling Kurt onto his chest. "You can't leave me, Kurt, please," he whispered into the darkness.

"I already have," Kurt answered.

And somehow, Finn knew that it was true. He would never have Kurt like this again, because Kurt wasn't his. He was married now. And Kurt had Blaine. And they could never be. Kurt pretended he couldn't hear Finn's quiet sniffles in the same way he pretended tears weren't leaking from his own eyes.