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Published:
2025-10-25
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A Better Son (Immoral Desires)

Summary:

Wooyoung wonders, is there anything sweeter than carnal sin? The line between his morality and his desires blur around San.

Notes:

There are non-con elements in this story despite San participating in sexual acts. Do not read if that makes you uncomfortable.

That being said... I’m sorry I love hurting you so much Sannie ><

(See the end of the work for more notes.)

Work Text:

Wooyoung used to work for San’s mother.

They had met when Wooyoung was hired to manage the finances of another new business venture she’d started, and they ended up getting married less than a year later.

It was true, what most people said about their relationship. Wooyoung had his eye on her wealth, but he couldn’t deny that she was beautiful. Unsurprisingly, his charisma had won her over and she had fallen in love with him, a younger man.

It was easy being her handsome trophy husband, he lived comfortably with her, all things considered and she was head over heels for him, but one thing Wooyoung hadn’t been expecting out of his new marriage was how stunning his stepson would be.

She had introduced him as San, a name as refreshing and as beautiful as he was.

He had soft, dark hair that brushed over his forehead, warm, brown eyes that reminded Wooyoung of a cat, and dimples that went deep into rosy, pink cheeks when he smiled.

Such a pretty face, Wooyoung thought. A son, prettier than his own mother.

At first, Wooyoung didn’t want to do anything to jeopardize his relationship with his wife. He definitely did not want to take advantage of San in any way, but San just constantly made it all too easy… practically dangling himself like bait in front of Wooyoung.

He already knew that San had never really had a father growing up, he was out of the picture early on, according to Wooyoung’s wife. So it must have been new and exciting for him now that he suddenly had a new father, a stepfather.

The new man of the house.

In Wooyoung’s mind, that was the reason why San acted the way he did, eager and ready to please his new father, wanting to make him proud, impress him, and see his mother happy too.

San’s mother had even had the idea of setting up ‘father-son’ dates so that Wooyoung and San could bond more and get to know each other, like game night, or movie nights, hangouts or barbecues with the guys… but it always ended up being a little too much for Wooyoung.

San was unknowingly tempting him, and Wooyoung was only human after all.

During movie nights, without fail, San would always cuddle up to him on the couch, sometimes even falling asleep on him, looking so pretty even in his sleep that Wooyoung had to restrain himself from caressing the soft skin of his cheek.

One time, Wooyoung and his friends had taken San out to the bar for a boys night out. He had invited a bright-eyed San along and learned firsthand that San was very much a lightweight despite his strong appearance– one who got very loud and giggly and clingy with whoever was beside him.

First, it was towards one of Wooyoung’s friends, who’d simply laughed it off since San had been extremely drunk, but then it had been Wooyoung himself that San was glued to, acting cute towards him and practically falling into Wooyoung’s lap every time he laughed, showing off those dimples every time Wooyoung cracked some silly joke.

After that, Wooyoung told himself that he had to keep an eye on San for safety, as his father. And so he stayed by his side the entire night, an arm around San’s waist or over his shoulders, telling himself he wasn’t enjoying San’s clinginess, or warmth, or his cute behavior, even though he most definitely was.

The fact that Wooyoung was only fifteen years older than San probably made San feel more comfortable being himself around him, and more at ease sharing secrets and personal stories with him.

Silly anecdotes, like how his first kiss was with the girl next door, and she’d slapped him so hard, he’d ended up crying; or shy secrets, like how he’d never had a boyfriend but was hoping Yunho from dance class would ask him out. He’d even shared more personal stories, things he’d never shared with anyone, like how San was the one who had to take care of his mother, cook his own meals even as a child, and be the grown up at home because his mother was broken after his dad had left them.

San wasn’t close to his mother, and it was obvious to Wooyoung with the way he was always craving attention from his new parent. San’s mother had also brought up to Wooyoung how San had no connection to his absent father. Whether it was of San’s own volition, or due to his father’s negligence, Wooyoung didn’t know.

But San had also opened up to Wooyoung about it once, when they’d gotten back home from a night out drinking with the guys.

He told Wooyoung that despite his lacking relationship with his mother, he could tell that she had been lonely for a long time, and that he was glad she’d found happiness with Wooyoung.

He’d hugged Wooyoung tight that night and told him that, to San, Wooyoung was like the father he’d never had.

Wooyoung felt guilty for enjoying his stepson’s company more than the company of his wife.

But after leading a stumbling, drunk San to his bedroom, he felt an even more horrible feeling rolling around inside him. San had mindlessly stripped down to his boxers in front of him and passed out on his bed, mumbling out a soft, ‘Love you, Dad’ before drifting off.

Pure, unbridled lust lurched like a monster in Wooyoung’s gut at the sight of San, at the sight of all that bare golden skin on the white sheets.

So young, and so pretty.

The way San moved and tossed around as he snuggled closer to a fluffy pillow, wrapping one strong thigh around it like he was hugging someone to sleep.

The way he huffed and sighed out those little sounds of his as he settled into bed.

The way his pink lips parted against his pillow as sleep took him, all the while unaware of Wooyoung’s lingering presence.

It got Wooyoung’s whole body running hot, and he was hard by the time he’d settled into his own bed beside his wife. Beside San’s mother.

He couldn’t deny it anymore, the fact that he was attracted to his own stepson.

The beautiful boy sleeping in the room down the hall.

Wooyoung had felt so wrong for watching, so wrong for wanting.

He’d wanted so bad to kiss those flushed cheeks, tell San he had never wanted someone else so bad, never wanted anyone as bad as he wanted him.

But he couldn’t, because that was his stepson.

San was off limits.

 

⫘⫘⫘⫘⫘

 

Time passed slowly for Wooyoung, and just as he’d promised himself, he had held back from confessing his rotten desires. Held back from doing anything that would cross that invisible line.

But he couldn’t hold back from looking at San the way he did when they spent time alone together.

San never seemed to notice the longing in his gaze either, which relieved Wooyoung from some of the guilt.

The less San knew, the better.

During the months that had passed, Wooyoung and his wife had been getting into arguments, fighting almost constantly about anything and everything, and San was getting visibly stressed out about it.

Whenever he was home from college or from work, that was all he would see and hear– his mother crying or Wooyoung yelling.

One day after a particularly loud argument, San had quietly opened the door to Wooyoung’s home office, polite as ever, even though he was clearly trying hard to hold back tears.

He told Wooyoung that he’d seen his mother storm out of the house crying.

Wooyoung was in a foul mood already, and not even San’s teary eyes and pouting lips could calm him down.

San circled the desk after Wooyoung ignored his pleas, ignored questions about why San’s mother was crying and running out again.

He knelt beside Wooyoung’s chair, asking so many questions with those brimming tears finally streaming down his face.

Asking things like why Wooyoung was so angry with his mother, why they weren’t getting along anymore.

San even admitted that he had been purposely spending more time with Wooyoung at home, all just so that Wooyoung would be in a happier mood, happy enough to stick around and be close to San’s mother again.

Wooyoung snorted to himself.

What a young, naive boy. San didn’t know that he was actually the reason Wooyoung couldn’t spend another minute with his wife.

Wooyoung didn’t want to give her attention, didn’t find her attractive anymore, because the fact was, all he wanted was his stepson.

He spent all his waking hours envisioning San’s thighs wrapped around his waist, imagining what his lips would feel like on his own. What his bare skin would feel like when Wooyoung touched him, how he’d react when Wooyoung made him come for the first time.

Wooyoung was angry about not being allowed to have San the way that he wanted. He was angry about having to stay with a woman whom he couldn’t stand just so he could be around San, the one his heart was yearning for more every day.

But right then, he’d been drinking and he wasn’t thinking straight.

He’d had enough of San’s pleading. His pitiful sobbing and relentless questions were overwhelming him, and Wooyoung tried to hold back from falling into an irrational, alcohol-fueled rage.

“San, that’s enough. Stand up, now,” Wooyoung gulped dryly around his words, trying to soften his voice. “Your mother and I… We’ve ended things. It’s really over this time.”

“Please… Please, Dad,” San sobbed and rubbed his damp face against Wooyoung’s thigh, hand clutching at the fabric of his slacks, “don’t leave mom… You make her so happy, and she loves you so much. She’d do anything to make you stay… I’d do anything too, so please… Stay…

Wooyoung’s heart was thumping in his ears. That word again.

Dad.

Wooyoung basked in the sick power it held over San, making him feel even more unstable as San’s other words rang out in his mind.

‘I’d do anything.’

He pushed San’s hair out of his forehead as the younger sniffled sadly, resting his head on Wooyoung’s lap, silent now that he was all cried out.

But just like that, the last of Wooyoung’s logic and morality was squashed to the ground seeing San’s pink nose and those glassy, pleading eyes looking up at him.

His thoughts were muddled with how desperate San looked on his knees, how he’d kept crying into Wooyoung’s lap, tears wetting his slacks. How easily he was placated from just the brush of Wooyoung’s fingers through his hair.

And worst of all, how close his mouth was to his half-hard cock, his warm breath ghosting over Wooyoung, seeping through the fabric.

Wooyoung brushed a thumb over San’s cheek, wiping the remaining dampness there. But his cock throbbed in his pants when San’s small hand gripped his wrist, keeping Wooyoung’s hand pressed against his cheek while his eyes slipped shut, as if he were in prayer.

“Please, don’t leave us…” His voice came out wrecked from all the crying, crying for Wooyoung to stay by his side, begging Wooyoung not to leave him.

In Wooyoung’s intoxicated mind, this meant San was desperate enough to agree to anything he asked.

San was offering himself up on a silver platter to him. Wooyoung would be an idiot to refuse, wouldn’t he?

If Wooyoung couldn’t have San the way he wanted… Maybe he could have just enough of him to keep his emotions at bay.

Wooyoung’s thoughts trudged into dangerous territory.

Maybe fucking San once would save his marriage. And then he would be happy, his wife would be happy, and San in turn would be happy too.

At least just once.

He licked his lips, soaking in the sight of San kneeling between his legs, looking so small before him.

The plan all worked out in Wooyoung’s drunken mind, and the words left his lips before he could rethink them.

“You’re a good son, San. You’d do anything to keep your mother happy, wouldn’t you?”

San perked up a little, his face slipping out from under Wooyoung’s hand as he knelt properly between his legs, back straight, nodding with fluttering lashes and a frown etched onto his pouty lips.

His small hand was still fisting the fabric of Wooyoung’s pants like he was afraid Wooyoung would just up and disappear.

“I would. I’ll do anything... I’ll- I’ll be a better son...” San’s chin wobbled as he spoke, eyes imploring.

Hearing that, Wooyoung sat up in his chair. He grinned down at San, not unkindly, holding San’s chin with one hand as he thumbed at his lips. They were soft and slightly wet.

San’s brows pulled together, looking confused at his actions.

“A better son, hm?” Wooyoung paused and slowly dipped his thumb in between San’s lips, his smile turning wolfish. San stared up at him, unmoving, eyes wide and stock still in his position, “Anyone ever tell you how pretty you are, kid?”

San gasped and shook his head slowly, looking a little scared. Wooyoung’s eyes traveled down to his shiny mouth again, feeling it tremble around his digit.

“A good son would always do what his father tells him to, wouldn’t he? He’d keep a secret to make his mother happy… isn’t that right?”

Wooyoung pushed his thumb in past San’s teeth and pressed down over his soft tongue, making San eke out a small shocked sound, shoulders rolling up reflexively, before Wooyoung pulled his thumb out altogether.

A line of drool followed and he smeared it over San’s lips before sitting back in his chair once more, hands clasped over the bulge in his lap.

He looked down at San’s expression from where he sat, drinking in the sight of him, how those brown eyes looked overcome with confusion, denial, the dawning realization of what his stepfather was asking of him.

Something in Wooyoung’s gut coiled hot in anticipation when San’s eyes landed on the hard bulge straining against his zipper.

Those pretty brown eyes, swollen, with lashes clumped together from crying, were tearing up some more just from gagging on his thumb.

Wooyoung imagined how pretty they’d look, wet and glazed over when San was gagging on his cock instead.

“And you’ve really never had a boyfriend before?” Wooyoung’s voice deepened, “Never had a man before?”

Wooyoung watched San process the question, eyes roaming his face and his figure slowly, tightening his thighs around his stepson’s shoulders.

Something inside him enjoyed the way they trembled against him.

 

⫘⫘⫘⫘⫘

 

San paused, hesitant at the eager tone of Wooyoung’s voice, his hand slackening its hold on his stepfather’s pants.

His eyes stung from the tears he shed as he took in his stepfather’s appearance. He looked as he always did, but something was wrong. Something was off.

Wooyoung wanted him to keep a secret. A secret that would keep his mother happy.

And now, there was a large bulge between his legs that San’s eyes were drawn to. It hadn’t been there when he walked in, but now, San couldn’t avoid it.

When he looked up, Wooyoung’s lips were stretched over his teeth in a different way than usual. It looked menacing and it sent San’s heart pattering nervously in his chest.

His stepfather’s thighs were pressed tight against his shoulders and he felt trapped somehow.

He could hear his question but couldn’t quite come up with an answer, his lips simply wouldn’t move.

Was this really happening?

His stepfather was asking him to keep a secret, asking him if he’d been with a man before. San knew what Wooyoung wanted from him.

Had he been with a man before? No.

The anxious little voice inside his head yelled at him to get up and run out of there. But San simply lowered his head, frowning, feeling somewhat ashamed in front of Wooyoung.

Maybe from his lack of experience as a man, or maybe because he seemed childish compared to Wooyoung. But if San was being honest with himself, maybe he was mixing up fear and confusion with shame.

He was afraid. His heart was racing and he could feel the blood rise to his cheeks as Wooyoung looked down at him.

He never thought his stepfather would be so crass, to be doing and saying things like this so brazenly. And put on the spot like this, San was unable to deny the truth that, even at 22 years of age, he was still very much a virgin.

He had already confided in Wooyoung that he hadn’t had time for love, always too busy caring for his mother all these years, practically being a parent to her instead of a child. Wooyoung was understanding back then, telling San that love would find him when he least expected it.

But now, Wooyoung only huffed out a laugh at San’s lack of response, his grin making him seem oddly thrilled at the prospect of San’s inexperience more than anything.

San’s embarrassment grew, blooming red across his cheeks as anxiety filled him.

“Hmm. Shame…” Wooyoung clicked his tongue and leaned forward, “Don’t worry, kid. Daddy will teach you how to make a man stay. We just have to keep it a secret, so your mom won’t freak out on us, hm?”

A pause.

“What do you say?”

San’s palms felt clammy as he grabbed a fistful of Wooyoung’s pants again. He did his best to swallow the bile crawling up his throat. Regardless of anything, why was Wooyoung speaking to him this way?

He couldn’t get a full breath in and his eyes nervously flitted around, searching for an answer he wouldn’t find. He was scared and unable to move, like he’d been frozen, turned to stone.

He wasn’t an idiot. He’d seen the way Wooyoung had looked at him before but he’d pushed away the gross thoughts, compartmentalized them– convinced himself that Wooyoung was looking at him proudly, happy to have him as a son, that he loved him like a father would.

But now the truth was undeniable and San had no choice. He had to keep his stepfather happy, or his mother would end up devastated and alone once again. She’d end up spiraling and no one would be there to pick up the pieces other than San. And San just couldn’t do that again.

He sniffled and swallowed hard, leaning in, his trembling hands reaching out to unbutton Wooyoung’s slacks.

He went as slow as possible, hoping that Wooyoung would stop him, change his mind, say the whole thing was a prank or a stupid joke made to embarrass him.

But Wooyoung didn’t.

He simply let San unzip him and even pried himself out of his boxers, his greedy hands guiding San’s hesitant ones to wrap around his hard cock, already burning hot and throbbing in San’s palms.

The shadows in Wooyoung’s dark office kept San from seeing his eyes, but he could see Wooyoung’s satisfied grin spreading slowly across his face, as he gently placed a hand on the nape of San’s neck, guiding San’s open mouth to wrap around the bitter head of his stepfather’s cock.

Despite the tenderness of the act, it felt like punishment to San. Wooyoung’s hand felt like a cage.

A thousand thoughts raced through his mind but the taste pulled him out of his thoughts every time.

San winced at that taste.

He could feel Wooyoung drip in his mouth as he sucked him in, something even more bitter oozing out and coating his tongue as Wooyoung moaned softly, whispering words of praise and encouragement.

He told San how well he was doing as San tried to keep his bile down.

‘That’s it… keep going’ and ‘You’re doing so well. That’s my boy’.

He said those words with a soft brush of his hand over San’s cheek, or while tucking San’s hair back behind his ear.

Gently, like he always did. Like he was proud.

Like hearing those words didn’t make San sick to his stomach. Like they’d make him happy to be doing this.

And maybe it did make some part of him happy. Maybe it satisfied his need for intimacy, his need to be close to someone, anyone. Maybe it satisfied his need to have a father in his life, someone to help him, guide him, praise him the way Wooyoung was.

But in the end, he was just being a good son to his mother, and to his stepfather. Wooyoung would stay if he kept being good.

San looked up at his stepfather’s face again, trying to gauge how well he was doing– if he was good enough yet.

His eyes leaked out more tears as he pushed himself to his limit, taking in half of Wooyoung’s cock despite his throat squeezing, trying to cough around the intrusion.

Wooyoung moaned and cussed, his fingers fisting San’s hair as he shallowly bucked up into the warmth of San’s pliant mouth, into the squeeze of his throat.

San tried to be good, tried not to choke too much, let Wooyoung put a heavy hand on the back of his neck, and with wet eyes, tried his best to suck him down. But he couldn’t help the whimpers that left his mouth as Wooyoung fucked into him.

His shoulders shook and he trembled as he took in more of him, but still, he tried to be good for Wooyoung.

He held his breath and sank down even though it felt like he was suffocating, buried his nose in the wiry hairs at the base of Wooyoung’s cock until the older man’s hips were stuttering against him, and he was coming hot into San’s mouth with a loud groan. Unrestrained and wild, like some sort of animal.

He pushed San’s head down onto his cock with brute force, bullying him into taking his full, throbbing length as San struggled to breathe.

San’s ears were ringing as he felt Wooyoung go deeper, burying himself inside the wetness of his throat with a vicious grip on his hair. Pinpricks of pain lit up all across his scalp, making him squeal, and the sheer size of Wooyoung had San choking pathetically around him.

And even then, even as that vile taste filled his mouth and lay thick on his tongue, and through the pain of being choked and handled like some common whore, San shut his eyes tight and tried again to be good.

Good enough for his stepfather, good enough to make him stay.

Seconds felt like hours, but San kept taking it as his snot and tears melted onto the skin of Wooyoung’s hip. The drool he’d choked out was frothing with cum against Wooyoung’s balls, and his throat clenched wetly around the girth of him until Wooyoung yanked him off.

He slipped out of his mouth with a slick, dirty noise and stripped his cock with his fist, adding to the mess on San’s face as San sputtered and gasped for air, holding onto Wooyoung’s thighs for support.

Wooyoung sounded hysterical, half laughing, half panting– his chest heaving as he painted San’s face with his cum.

He smeared his still hard cock all over his own spend and spread it across San’s cheek, slapping it onto his lips and chin, making sloppy, wet noises as San just knelt there and took it, eyes downcast.

“I’ve wanted to do this from the moment I laid eyes on you. Pretty face like that… just begging to get cum on…” Wooyoung’s words were slurred, sounding like he was high off of something.

His hand, still wet with cum and spit, slid down to wrap around San’s neck, under his jaw, constricting his breathing slightly as San’s hands wrapped around his wrist in panic.

“You like my cock down your throat like that?”

San went still at that, body tense and rigid, reeling from the shame those words stirred up in him. He squeezed his thighs together, willing his softening erection away.

He didn’t like it. He didn’t want to like it.

He hated it.

“Hey.”

A hand suddenly gripped San’s face a little too hard, squeezing his cheeks and urging his gaze upwards, “Look at me when I’m talkin’ to you, kid.”

San’s empty gaze fell into Wooyoung’s piercing eyes and he felt somehow disappointed to see that it was just Wooyoung in front of him. Not some horrible, ugly monster.

Just Wooyoung.

He was still handsome, still in his work clothes. Still his stepfather.

San’s vision blurred and a stubborn tear slipped out of the corner of his eye and rolled down his cheek, mixing with the mess of cum still there. He sank his teeth into his lip to hold back a sob, chin wobbling in Wooyoung’s grip.

“Atta boy,” Wooyoung’s face softened and he smiled at him a little, something tender that didn’t match what had just happened.

His gaze was intense but adoring. It was almost like he was just his stepfather all over again, except San had his cum on his face and he’d had his cock down his throat not two minutes ago.

“Open up.”

Wooyoung wiped the cum off of San’s face with his hand, and fed it into his mouth, a mockery of how he’d wiped his tears earlier, “Such a pretty mouth…”

His voice was soft. His fingers ran along San’s wet bottom lip, glossing it over with cum before sliding the digits into his mouth, prompting him to suck. Over and over, till his face was all but wiped clean.

San simply obeyed, sucking and swallowing around the knobby knuckles without thinking. But he wished Wooyoung had never spoken.

He wished Wooyoung had kept all those thoughts to himself so he could compartmentalize again, so he could separate his stepdad Wooyoung and this monster Wooyoung from one another.

He wished he’d never looked up so that he wouldn’t have to see Wooyoung smile like that. So softly, like he was fond, proud.

He could feel the corners of his lips pulling down. Just knowing that Wooyoung had wanted to do this from the moment his mother had introduced them to one another tainted every memory San shared with him.

It made him sick to even think of their father-son dates now. He felt like a fool, like he could never trust another person again. Like he was too stupid to figure out what had been right in front of him all along.

But no matter, he had still made sure to be good all throughout, even if he couldn’t stop himself from crying with Wooyoung’s softening cock rubbing against his face. Even if he hated the taste of it, the heavy, overbearing feel of it in his mouth and the humiliation he felt being cum on like this– being dirtied like this, by his own stepfather.

Because if he kept being good like he was tonight, Wooyoung would stay with his mother.

This wasn’t new to San. History was repeating itself, and once again, he had to step up and be the adult, be his own parent.

Even if it meant taking his mother’s place. Even if it meant sleeping with his stepfather.

He would be a better son to keep his family together.

San looked up with glassy eyes.

“You’ll stay now. Right, Dad?”

Wooyoung’s hand caressed his cheek, thumb running over his damp lashes gently.

“I’ll stay.”

Notes:

Thank you for reading. This one’s a little dark but I hope you enjoyed the smut just as well.

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