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The first time Riku met Yushi, he could see the string that connected his thumb to Yushi’s pinky, a vibrant dark red string that moved whenever he moved. He was still five years old back then, too young to understand the meaning of soulmates, let alone what a string does. So he decided to cut the string with his safety scissors, thinking that they shouldn’t be connected like this. Yet, every time he tried, he couldn’t succeed, and neither could Yushi.
It was then that their moms explained it to them, both looking surprised that their sons found each other’s soulmate. It took them a few times to understand the concept of soulmates, and in the end, they became inseparable, spending too many hours together. And Riku always felt glad that they met early, because unlike other people, they were able to experience everything together. Whether it was the first day of school, or the first friend he met through class, Riku was there to guide Yushi through it all, and steered him away from bad decisions.
And because they met early, they both naturally built a resistance against the withdrawal symptoms, being able to last at least a week before succumbing to withdrawal sickness. It was a good thing for them since Yushi would travel a lot for his soccer games during high school.
And as research has shown, when soulmates have been together long enough, each will develop a unique ability that helps them better connect with their soulmate. Like having the ability to know when their soulmate is nearby despite being 10 km away, or the ability to withstand the withdrawal symptoms longer than the average timeline.
For Yushi, his ability was being able to pacify Riku with his touches. Whenever Riku was upset, or feeling frustrated due to life, all Yushi had to do was touch him and Riku would immediately calm down, as if the sensation calmed his heart. Yushi always thought of it like some weird superpower, but it worked every single time. Nevertheless, Riku would claim that it’s unfair, that he wanted to stay mad at Yushi longer, but deep down, he was glad. He didn't want Yushi to stop caring about him.
Meanwhile, for Riku, he could easily tell Yushi's emotions through their string’s bond. It would warm up when Yushi felt happy, stung him when he was mad, and became freezingly cold when Yushi felt sad. He could even tell when Yushi felt horny; it felt like a course of pleasure entering through his thumb, intense and raw .
This also meant that he could tell when Yushi felt attracted to someone, even if it was just a simple crush. He knew that just because they are soulmates, it doesn't mean that they can't find other people visually attractive. But for Riku, he was only attracted to Yushi, finding him the most pretty person ever. He simply wished that Yushi would feel the same way about him.
So he would huff in an irritable fashion, pouting and spitefully hiding his hands in his pockets, refusing to let Yushi touch him in retaliation. Despite that, his anger never lasted long, feeling guilty the moment he could feel Yushi’s sadness. He ended up apologizing for being mean before hugging him tightly.
Over time, Riku learned to accept Yushi's flaw and eventually, they understood each other's limits and how to handle it.
As the years passed by, their string of fate grew thicker over time, collecting all of their sensual moments for the past fifteen years. For every kiss, a thin, dark red string would get added between them, and for every hug, the string would wrap happily around their bodies, clinging into their skins. And whenever they had sex, a dark blue string would get added, as if a constant reminder of how much they love each other.
The change of color is caused by the chemical reaction of their bodily fluids reacting to their string. Riku finds this fact to be funny, smiling every time he notices a new blue string between them, but Yushi finds the idea to be exciting . He keeps thinking about changing the color of their string to blue one day, finding the color to be more pretty.
But for now, it remains a mixture of blue and red, intertwining with each other, reminding them that their love will keep growing.
Even for today, during Yushi's birthday, Yushi pouts at Riku, silently asking him for some sex instead of celebrating his birthday with a cake.
And Riku doesn’t mind it. After all, they've been trying for a baby lately and Riku gets horny enough at the idea of breeding Yushi every day.
Ever since Yushi tested positive on becoming a carrier, Riku has been too happy about it. It's the idea that Yushi can carry his child one day, making him smile in imagination.
There was always a 50% possibility for every soulmate couple to reproduce, and Riku prayed hard for them to have that option. If they ended up not being able to reproduce, Riku would be forced to produce an heir with a widowed carrier, and he'd hate that option.
So he’s been working hard to put a baby inside Yushi one day, imagining the day his soulmate will walk around with a round stomach and a sexy glow. He wants to succeed because he refuses to let someone else breed Yushi one day. As long as Yushi produces an heir for the next generation, they won't need to worry about that possibility.
It's why Riku likes having Yushi face down at the bed and a pillow is placed under his hips, creating the best position for the sperm to travel down towards the womb. And sometimes, he'll purposely grind against the womb opening, stubbornly thinking he can slip the tip in.
But for now, Yushi is simply bouncing his cock slowly, feeling the length to drag sensually against his walls.
“Riku~” Yushi moans into his ear because he feels overwhelmed every time he feels the tip reach deep within him.
“Baby, you feel amazing,” Riku groans against his neck. “You drip so much when I do this.”
He thrusts again, this time brushing against a sensitive spot and Yushi claws against Riku's back, whining loudly.
“More,” he demands, slowly riding Riku while gasping a little.
He feels his hole widens from the stretch, moaning as the cock slides in deeper. He used to be scared of the size, thinking his hole will get loose over time, but God , he loves how thick it is now. The way it rubs sensually against his walls, massaging all of his favorite spots before reaching a new spot. It always causes him to moan loudly in pleasure, whimpering and begging for more.
Sex with Riku has always been too good. He's even willing to warm up Riku’s cock all day long, as long as it means he can feel it inside of him.
And as for Riku, he tends to feel overwhelmed by the emotions, realizing he can feel Yushi's emotions too. The horniness, the happiness and the craving to have more of Riku. He can't help but get turned on even more, causing himself to get reckless during sex.
Like randomly spanking Yushi’s ass as the younger bounces on him, or whispering dirty words into his ear, asking him if he's Riku's little slut.
And lately, they've been trying out rough sex. Like bending Yushi over a desk and fucking him without a care. Or pinning his wrists into the bed, making him overstimulated before letting him cum.
And tonight, he thinks about fucking Yushi from the back, forcing him to take it all and ignoring his complaints. Yushi has always loved the idea of being submissive under him and it's been a while since they did this. Riku particularly wants to see the younger claw the bed from overstimulation and try to run away when the pleasure is too much.
But before he thinks about doing it, he sees Yushi's phone lights up, and he can see the name of some guy they met days ago. Riku doesn't even know why that bastard is calling Yushi, but he feels irrationally jealous, stalling his actions.
“Rikuuu,” Yushi whines loudly, wondering why his soulmate has stopped fucking him.
“He's calling you,” Riku mutters in jealousy, feeling his emotions control him before thrusting roughly without a care. “Why is he calling you?”
Yushi whines at the sensation, feeling the tip jabs against his wall and his body shivers in delight. He's gasping when Riku thrusts again roughly, wrapping his arms around Riku's shoulders.
“Did you give him your number?” Riku asks childishly with a whine, not stopping his movements, groaning when Yushi's wall slowly tightens around him. “You're mine ,” he growls possessively before grinding his cock against Yushi's sensitive spot, noticing that Yushi will cum soon.
“Yours,” Yushi whimpers before suddenly feeling his orgasm approach. He thought that Riku would forcibly stop it, but instead, Riku tugs at his cock repeatedly, and his orgasm comes too quickly. It makes him trash and moans against Riku, whimpering as he feels sensitive from the pleasure.
As the pleasure dies down, he can feel his hole wraps tightly around Riku’s cock possessively, as if waiting for the next round. He hums quietly before moving his face to kiss Riku's lips, feeling a little clingy as usual. Their tongues tangle as Riku caresses his skin, slowly building up to round 2
“I'm yours,” he says to Riku again, kissing his lips before moving his ass again.
He rocks against the cock now, feeling ready to be bred this time.
Riku nuzzles against his neck in comfort, smiling at his reassuring words before patting his butt. It's a silent signal that they should change position now.
Yushi slowly pulls off the thick cock, whining at the loss of sensation before he lays on his stomach. He raises his ass up into the air and covers his face against the pillow, feeling a little embarrassed in this revealing position.
But he likes how good it feels when Riku’s cock can reach deeper within him.
Riku also finds this position to be sexy, gliding his hands across Yushi's back, enjoying the soft skin under his touch before he parts that cute ass. He slides his cock between the cheeks before aiming his tip into the entrance. Yushi moans while pushing backward, anticipating to feel that hard cock inside him again, and Riku slowly thrusts inside, moaning at the sensation.
Riku's cock feels bigger than usual in this position, simply because he can slide it in better, aiming immediately to the deep end. It easily nudges against the opening of Yushi’s womb, bumping into it repeatedly, causing Yushi to whimper lightly each time.
He claws against the bed whenever Riku grinds against the opening, stimulating it so it'll open up a little and accept his sperms. He tends to whimper a lot during this process, making pretty noises when the tip jabs too harshly, or moaning like a horny slut when the tip flicks against the entrance.
His pre cum drips continuously into the bed and Riku groans each time he feels the hole tightens.
“Baby, you're so tight today. So greedy for my cum,” Riku huffs out as he thrusts. “You want my cum, don't you? Want me to breed your empty hole?”
“Y..yes,” Yushi moans out.
“Should I make you full?” Riku groans at the thought. “I bet I could make your womb full of my cum. You'd love that, won't you?”
“W..want it. Gimme your cum,” the younger whines as he imagines it.
“So perfect,” Riku mutters as he squeezes an ass cheek. “ My Yushi.”
“Yours,” Yushi moans before whimpering in sensation when Riku decides to lean forward, covering Yushi's back, and reaches out to grab the phone. “Riku?” he asks in a whiny tone, wondering what the elder is up to.
“Let’s tell him. Let's tell him how slutty you are for my cock,” Riku says before unlocking the phone.
Yushi groans at the idea, somehow realizing his exhibitionism kink can be extended this way.
“So moan prettily, or you get nothing ,” Riku warns him cruelly.
Yushi nods tearfully before hearing the phone rings.
Riku makes sure to give a hard thrust, reminding him of his task, causing Yushi to yelp at the sensation.
“Yushi! You called!” A male voice echoes out from the phone.
“H..hi,” Yushi answers breathlessly.
“I know it's your birthday, but if you're free, let's hang out!”
Riku frowns from hearing it, thrusting cruelly, jabbing the entrance of his womb.
Yushi bites his bottom lip, withholding the moan before gasping out.
“C..can’t,” he ends up blurting out in a rush. “I have a soulmate.”
“So?” The guy scoffs. “Just don't tell him.”
Riku tightens his grips on Yushi's hips, thinking how he wants to kill this guy one day. But for now, he grinds his cock into Yushi, hoping to make Yushi moan out loud by accident.
Luckily, he didn't have to wait long.
“Noooo,” Yushi suddenly whines out loud, feeling overstimulated.
He can feel his hole constrict repeatedly against Riku's cock, a tell-tale sign that he's approaching his second orgasm. But most of all, he can feel the entrance of his womb slowly opening wider, since Riku’s tip keeps getting stuck before slipping away.
Just a little more stimulation, and Riku can easily press the tip against the opening and aim towards the inside. He'll cover Yushi's womb completely with cum. The idea makes Yushi moan in anticipation.
So he doesn't even care anymore by now, moaning when Riku jabs the entrance again.
“...Yushi?”
“I can't,” Yushi whines out. “Riku… he's… “ he struggles to form a sentence before he ends up blurting it out loud. “Cock so good.”
Riku scoffs loudly behind him, smiling too happily at the confession.
“ Thick ,” Yushi confesses randomly while moaning. “Want your cum,” he whines in the end, glancing backward with a pretty pout.
“Fuck,” Riku mutters, loving that sight. He immediately hangs up because the whole purpose was just to piss off that guy, not to let him jack off to his soulmate’s moans.
Plus, he can feel how horny Yushi is by the constant flow of pleasure into his thumb. The realization makes him unhinged, feeling the need to breed Yushi with his cum, soon .
“ Fuck . Baby, I'm so close. You feel so good,” Riku mumbles to himself. “Gonna breed you so good. I can't wait to see you round with our kid.”
“Yes,” Yushi moans in agreement.
“And you'll give me more, right?” Riku asks with a grunt. “I'll keep you pregnant every year.”
“Y..yes, yes,” Yushi agrees without thinking, simply lost in pleasure. He just wants to feel Riku's cum flood within him.
So Riku grunts repeatedly, grinding his cock deeper, stimulating the womb’s entrance a few times before feeling it open completely. It's never going to be wide enough for him to stick his tip inside, that's impossible, but it's wide enough for Riku to rub the tip tantalizingly against it.
And then he forcefully shoves his tip against the entrance, forcing Yushi to shriek in reaction, feeling the tip struggle to enter it. The sensitivity is too much for him and he moans loudly against the pillow as he cums. His cum sprays messily against the bed as he ruts against the sheet, whimpering in oversensitivity.
Meanwhile, Riku moans in a low tone as he cums, feeling his tip sprays into the entrance, forcing most of his cum into the hole. His body shivers in pleasure as he mouths Yushi’s neck and nibbles a mark. He then creates a trail of hickeys, waiting for his cock to finish ejaculating while grinding against Yushi's walls.
Yushi can only moan unabashedly as the cum floods inside of him. It feels thick and heavy, coating his womb in every corner, slowly swimming to find a viable egg. The cum keeps sloshing within him, moving around as Riku grinds his cock against his walls, enjoying the remnants of his orgasm.
He whimpers lightly as exhaustion starts to arrive, and he feels slightly sleepy, silently praying that it’ll take. He just wants to make Riku happy again.
For now, a new blue string forms between them, too unsuspecting for their eyes. But it twinkles happily as another proof of their love.
**
4 months later.
Yushi isn't showing yet, but there is a baby growing inside of him. They already went to the doctor a few weeks ago, printed a photo, showed off their tiny fetus to everyone before cuddling again in bed.
And they still fuck regularly, creating blue strings every week and whispering dirty words to each other as usual.
Most of all, Riku finds other ways to stimulate Yushi these days. He can't grind against the womb entrance anymore, so he plays with Yushi's nipples instead. He twists them cruelly and he flicks them all the time, loving the way Yushi's hole tightens each time.
Today, he sucks those nipples harshly. Gently biting them before sucking again, imagining he can draw out milk from them. Yushi won't be able to lactate enough milk to feed their baby, an unfortunate reality, but his body will still change accordingly. His chest will grow a little bigger and his nipples will get round and puffy, as if preparing itself for the milk that will come.
Riku can't wait for that.
For now, he simply sucks them while slowly fucking Yushi into their bed, hearing his soulmate gasps every time he sucks a little hard. He’s also enjoying how Yushi claws against his back, feeling happy whenever he overstimulates him.
“Rikuuu, stop it,” Yushi whines with closed eyes. “You said – gasp – you said we have to go soon.”
“It's fine if we're late,” Riku grunts as he thrusts, finally letting go of the nipple.
“But you promised,” Yushi whimpers as he feels Riku's tip rubs deliciously against a sensitive spot.
“But you feel so good baby. So wet and tight for me. I bet I could stick another baby up there if I shove it harder,” Riku chuckles into his ear.
“Nooo,” Yushi whines. “You can't,” he huffs. “ Mine ,” he says possessively, not wanting to share Riku with more than 1 kid just yet.
“So needy ,” Riku teases while making Yushi bounce on him. “Why don't you make me cum and I'll be good today?” He taunts Yushi with a smirk.
Yushi whimpers at hearing the challenge before deciding to do it. He knows the easiest way to make Riku cum anyway, after years of experimentation.
**
At 7 months pregnant, Riku finally tastes Yushi’s milk. He won't produce a lot, but it's enough for Riku to suckle it in the morning, drinking his breakfast milk happily.
The doctor encourages them to empty Yushi's chests every day. He claims that constantly milking Yushi will help him produce more milk in the future. Especially since most men can only produce one bottle, not enough for the baby during the early months.
So Riku makes it his challenge to milk Yushi every morning, before fucking his hole quickly, to pacify his horniness.
This morning isn't any different. He's sucking Yushi's nipple quietly while gulping down the milk, carefully not waking Yushi because the younger one was tired last night. He simply sucks it without touching his body, making tiny suckling noises before switching to the next nipple. He can feel Yushi's happiness radiate in his thumb, mixed with a constant dose of horniness.
He’s almost done milking him when Yushi finally wakes up with a small moan, realizing that Riku has been milking him for a while.
“You're so pretty today,” Riku mumbles to him after letting go of the nipple, rubbing his swollen stomach.
“Riku,” Yushi whines with a small pout. “Fuck me.”
Riku can feel Yushi's neediness through their string.
“I will baby,” Riku promises before slipping off his pants quickly. His erection is already fully hard, impatiently waiting.
Ever since his stomach started showing, Riku can't fuck Yushi from the front anymore. So they end up fucking sideways these days.
He will shove his lubed cock in without warning, knowing that Yushi likes it a little rough. And he'll go slowly, stimulating the inside before fucking him roughly. Yushi can't last long these days, getting exhausted quickly, so Riku tends to rush it so Yushi can rest again.
Yushi moans loudly during it, enjoying the stimulation before begging for more as always. He even grinds backward, feeling greedy for that thick cock to keep fucking his hole.
And soon, his chest will fill up again and his milk will start to leak out, trailing down across his body.
Riku groans in desire, wanting to drink his milk again, but he knows it's impossible in this position. Instead, he keeps fucking him thoroughly, watching as the milk leaks out everywhere and whispering dirty words to Yushi's ear.
“Baby, you'll make more milk for me, right? You'll let me suck them every day? Little bean don't need it. Your Riku does,” Riku begs into his ear. “I’ll keep fucking this tight hole of yours. Your sweet , tight hole. How are you still so tight when I keep fucking you?” He shoves it in again forcefully, bumping against the womb.
“Riku,” Yushi whimpers, feeling his hole flutter in reaction.
“Tell me, baby,” Riku moans into his ear. “Tell me how slutty you are for my cock.”
“I want it,” Yushi moans. “Please Riku. Keep fucking me. Don't stop,” he begs prettily with his eyes feeling a little wet.
“Is it good?”
“Yes,” he immediately says. “So good. Please Riku. I want it,” he grinds against Riku, trying to shove more of his cock inside, like the horny person he is.
Riku groans into his ear in reaction, rubs his stomach teasingly, and squeezes his chest firmly, loving the way Yushi’s milk leaks into his palm. He flicks the sensitive nipple as he grinds against the overstimulated wall, feeling it constrict around his cock.
He can feel it, whenever Yushi is close to orgasm, and he knows this will be an intense one, feeling the pleasure intensify in his thumb.
Yushi doesn’t give a warning before he cums with a loud whine, trashing in Riku’s arms because his thick cock keeps jabbing against a sensitive nerve. Riku rocks into his hole with a few more thrusts before ejaculating deep inside, groaning into Yushi’s neck.
The bed sheet is thoroughly soaked with milk and cum, but neither cares about it as Yushi yawns happily and Riku kisses his shoulder lovingly.
His cock is still nestled inside, slowly returning to its normal size, but Yushi likes having it in him for a bit longer.
Their string of fate finally wraps around their bodies, reminding Riku that it’s been looking more blue lately. Only traces of red can be seen, simply because they’ve been fucking more than kissing these days. He’s not surprised though. He doesn’t think they’ll ever stop wanting each other.