Theory
a/n: If these pairings are not your thing, then do not interact! I enjoy writing rare pairs and will not tolerate hate or harassment from this Kinktober request I received. <3
tags: Reiner Braun x Mikasa Ackerman, cuckhold!Eren, college au, repressed feelings, teasing, oralf!recieving, slight degradation, pronebone position, smut.
kinktober day six: cuckhold for anon
"This feels like a trap."
Reiner closed his laptop finally and gave Eren a look across from him, noticing the man was being completely serious about the offer he just gave him.
"It's not a trap."
"It's worded exactly like a trap."
Eren sighed, throwing his head back and going through all the dramatics. Reiner sat there with his arms crossed, not even letting the idea take wind inside him because it was too good to be true.
"Then let me reword it." The man groaned, clearing his throat and turning almost mockingly serious. "Mikasa and I have talked and we want you to fuck her while I watch."
"That doesn't sound any different than the first time you said it."
Now him and Eren were in a staring match, waiting for the other to say something and break the tension. Reiner would've agreed without question if it weren't for the massive crush he had on Mikasa already. They were talking at one point, a year and a half ago. Reiner remembers it going well, Mikasa reciprocating his feelings (or so he thought) and then the conversations between them dying down. Not even a month later he found out she was dating Eren, unintentionally driving the stake deeper inside him.
On the other hand, if Reiner was serious about his offer, then maybe this would be the one opportunity to have what he almost had with her. It's not everyday you get to fuck the girl you still have feelings for with her boyfriend watching. And Reiner didn't have anything personal against Eren, maybe just a tinge of resentment for dating Mikasa, so this could get a small get back at the man for riding away with her into the sunset.
"Alright, yea I'm down."
Eren smiled a little, crossing his arms over his chest and giving a small nod.
"We'll talk and I'll send you details later."
Much later in the day, after Reiner had gotten back to his student apartment is when Eren sent him a text with the details he promised. They'd agreed the weekend would be better and thank god that worked for Reiner too, sending a confirmation text back that the weekend worked good for him too.
He was nervous, that he'd admit while on his way to Eren and Mikasa's shared place, hands shaking on the steering wheel the entire time.
Mikasa answered the door, a gentle smile on her lips as she welcomed Reiner in.
"Eren just got out of the shower, he'll be out in a minute. Do you want anything to drink?"
"No I'm good, thank you though." Answering as he stood there awkwardly by the front door still, hands in his pockets and thinking if he wanted to get out of this.
Eren entered a moment later, hair still damp and resting on his shoulders. Mikasa came around from the small kitchen to stand by him, whispering something in his ear. It could've been anything, but Reiner felt like his gut was already bubbling with so many nerves that he might hurl the lunch he had hours ago if he kept thinking they were whispering about him.
"You can come in here Reiner." Mikasa called, starting to follow behind Eren to the bedroom. There was no turning back at this point, his feet moving on their own as he approached her, admiring her subtly. She wasn't wearing any makeup like she normally was and Reiner still thought she looked beautiful.
The bedroom already had the mood lighting set, warm dim lights making it possible to see still but conceal in subtle shadows at the same time. Mikasa sat on the edge of the bed, Eren in a chair he had to have pulled from their living area, facing the bed. They both look comfortable for what was about to happen, not getting the sense that either of them were nervous.
"We want to go over some rules before we start." Mikasa said, her voice so gentle and sweet Reiner felt a bit of nostalgia come over him from all their late night phone calls back then.
"Mikasa is in charge." Eren cut in before she could even say whatever it was, stopping to shoot her boyfriend a dirty look, that just rolled off his back with a shrug.
"Essentially, this was all my idea. I don't want to say 'I'm in charge' because I'm pretty comfortable with most things and I trust you Reiner."
Neither of them said anything further, Reiner still stuck at the part where Mikasa said this was her idea. What conversation did she have with Eren that even got it to this point? Reiner had a lot of questions but not enough time to get those answered, seeing as Mikasa had shed her sweatshirt she was wearing, now in a thin gray spaghetti strap tank top.
Fuck, Reiner already felt like he was loosing a bit of his control, her tits sitting perfectly on her chest, just waiting to be groped and teased and she was giving him a look that Eren probably received often right before they fucked.
"Don't be shy, Reiner."
It was Eren's taunting tone that irritated him but spurred him into action at the same time, taking steps to approach where Mikasa was sitting on the edge of the bed. He knew he was blocking Eren's view, defeating the whole purpose of this, but Reiner just wanted a second to admire Mikasa. She looked up at him with these big doe eyes, wetting her bottom lip and lying back on her elbow. Her sweatshirt had been hiding the tiny black shorts she was wearing, and Reiner saw how fucking tight they were around her hips and thighs. Fuck him, he really wouldn't be able to control himself.
"I've heard a lot about you."
And the rest of the world drowned out into nothing, only hearing her velvety smooth voice as she subtly pulled the hem of her tight tank top to reveal a sliver of her stomach.
"In what way?" Looking down at her, shamelessly admiring her body and wondering how it would feel to press his lips to her milky white skin, run his tongue along her dips and curves.
"That girls around campus seek you out, for certain things."
Hm. Reiner hadn't realized he had such a reputation in that regard. He was like every other single guy, hooking up with girls when the opportunity presented itself, never thinking it'd become chatter.
"Is this where this idea of yours is stemming from?"
Mikasa lightly laughed, sitting up all the way reaching out to slip her hand under his shirt, just above his belt, making Reiner suck a small breath through his teeth. Her hand was so soft, and delicate, her touch was electrifying and a part of Reiner wished this moment between them was happening under different circumstances.
"It's just a theory I want to test."
Reiner smirked, reaching for the hem of his own shirt and pulling it over his head, giving Mikasa a view of all his hard work at the gym over the past couple of years. She liked what she saw, standing from the bed and pressing herself to Reiner's chest, hooking her fingers into the belt loops of his jeans and pulling him closer.
"Eren fucks me good, but I feel like you could fuck me better."
The confession was nothing more than a whisper, no way Eren would've been able to hear that, making it just for Reiner's ears.
Heat simmers low in Reiner's gut, looking down at the woman who slipped from his grasp seeing that any man would be lucky to have her, only a shame Reiner couldn't.
"I guess depending on how all this ends, you can keep your answer between us." Placing his hand on her shoulder, moving one of the thin straps down, and doing the same to the other side.
Eren cleared his throat, reminding them both that he was in the room and technically suppose to be watching. Reiner didn't react, looked over his shoulder and smiled in a feign apologetic way.
"Sorry, just admiring your girlfriend, got carried away." Which wasn't a lie, everyone knew that, only what was said kept between him and Mikasa. Eren still looked slightly suspicious and Reiner briefly wondered if he knew about him and Mikasa's brief talking stage. I guess it wouldn't matter if he did, he still agreed to watch.
Stepping to the side as he unbuckled his belt, Reiner steps out of his jeans and thinks momentarily what the best way to position himself and Mikasa would be on the bed without obstructing Eren's view.
Before he could even make a suggestion, Mikasa was already lying down, head facing the foot of the bed, solving that small problem. Reiner doesn't bother to hide his half hard cock that began to protrude through his boxers, climbing on the bed and positioning himself to hover over Mikasa. He wanted to take his time but was also eager to have his way with her, knowing he couldn't take too much time to consider before one of them made the decision for him.
Glancing at Eren before dipping down, Reiner formulated a plan in his head on how he would make this the best for him and Mikasa, remembering how she said she trusts him and thought about how far that trust would stretch in this scenario. Slowly, his lips met hers, parting them gently and slipping his tongue past, unable to help himself. Mikasa hums and reached for the back of his head, cradling it as her nails ran along his scalp. His vision exploded with stars, kissing her finally after never quite getting that far with her before. It was slow, passionate almost the way they kissed, like they were true lovers. Her back arched off the bed, enticing Reiner to run his hands down her sides, slipping under her tank top.
They only just kissed for a while, lost in the art of their lips moving together in a gentle dance, a sort of longing interlaced between. Reiner wished he could truly take his time, explore and worship her body like he's always wanted to but knew the third party would get impatient.
Intensity was soon felt in the mix of their melding mouths, Reiner brushing the underside of her tits one too many times to where Mikasa was moving in a way to subtly tell him to take it off. He followed her silent instructions, lifting the tank top completely, her tits bouncing against gravity.
Jesus Reiner felt like a dog with how he was salivating, taking one in his hand and giving it a squeeze. She moaned softly, partially laying her head off the end of the bed, looking at Eren. Reiner caught a brief glance of the man, satisfaction written in the way he approved, shifting in his chair like he was finally getting the action he wanted out of this.
Reiner kissed up her sternum, between her tits and at the top, staring at her other tit and kissing lightly over nipple. Her most vocal reaction came from that, moaning and arching slightly, spurring Reiner on to take it into his mouth finally. Mikasa squirmed and Reiner used his body to keep her pinned, sucking the bud and swirling the tip of his tongue. Eren stayed focused on her and her continuous moaning and gasps, even reaching forward to cradle one side of her face.
He made sure to give each one equal attention, sucking, biting and swirling, giving her more than what he's given any girl in the past. Mikasa moaned pathetically when he twisted one of her nipples between his thumb and index while tracing the other with his tongue, attempting to grind against something. Reiner chuckled and came off, slipping his boxers down and returning to Mikasa sprawled out before him. Her tiny black shorts were still on, but Reiner would get there shortly, working his way down from her sternum with hot open mouth kisses, slipping in a few nips with his teeth, stopping right when he got to the waist band.
"Woah, hey."
Reiner stopped upon hearing Eren's cautious words, sitting up a little and looking at both of them.
"What?" Mikasa asked, almost annoyed that Eren had interrupted Reiner.
"I thought you didn't like that?"
Oh now it was getting interesting, especially after Mikasa shared her theory with him earlier.
She hesitated on her answer and the last thing Reiner wanted was for them to get in an argument or have Eren offended.
"She said she's comfortable with me doing whatever. If she doesn't like it I'll stop." Looking at Eren and hoping he didn't come off too arrogant, knowing he heard Mikasa say exactly like before they started. "Just tap me or tell me to stop." Saying to Mikasa and seeing her gratitude for saving her a second ago.
Eren sat back in the chair, adjusting his shorts and giving Reiner the smallest ego boost. He hadn't really begun and yet he had her boyfriend trying to hide the boner from watching him suck and pay with her tits.
Resuming where he left off, Reiner hooked his fingers behind the fabric and pulled the shorts down slowly, kissing below her naval and expecting to run into the barrier of her panties, just to discover she wasn't wearing any.
"Didn't see the point of any since you were coming over."
Reiner had a witty comment on the tip of his tongue, but held it and settled for a pleased chuckle, throwing her shorts to the floor and hooking one of her legs over his shoulders. His cock throbbed against the bed as he stared at her cunt, already wet and it was all because of him. Reiner took his time, caressing the bent knee and kissing down her inner thigh, going as slow as he could.
He could practically smell her arousal the closer he got to the center of her legs, feeling like a crazed and starved animal the nearer he got. Mikasa was running her fingers through his hair, sending shivers down Reiner's spine. His lips were inches from her pussy now, letting out a shaky breath right before running a flat tongue from her entrance to her clit. She tasted fucking divine and Reiner hated that this may be the only time he'd get her like this, so he had to savor as much as he could.
Over and over his flat tongue parted her folds, easing his way into pleasing her before diving in head first, knowing this might be something Eren won't be able to top, at least Reiner could leave with that bit of satisfaction.
Mikasa arched and choked on her moans, gripping Reiner's hair and trying to get him to give her more. He couldn't resist, as he was discovering, so to please her, Reiner focused on her clit. She cried out in a way that had Eren locking his gaze onto him, too many emotions swirling in his eyes for Reiner to decipher, but he knew that he was achieving something Eren obviously couldn't.
Laughing against her clit, coming off for just a second to wet two of his fingers, Reiner traced letters and shapes onto the sensitive bud, her leg trembling over his shoulder.
"So perfect." Muttering to Mikasa who now sat up on one of her elbows, her eyes glossy with pleasure and lust, watching the way her worked her clit against his tongue.
"Keep going." She begged, falling back down onto her back and looking back at Eren, trying not to grind her hips into Reiner's mouth.
The finger he'd been teasing at her entrance started to push in, Mikasa crying out his name and arching at beautifully. She was tight and warm around his finger and all Reiner could think about was how that was going to feel here soon.
"Enjoying yourself baby?"
Eren asked, smiling when Mikasa nodded, already at a loss for words. Reiner noticed the other man had been palming over his crotch and decided he wanted to see Eren a mess while he fucked his girlfriend better than he could.
Shoving in a second finger and sucking her clit back into his mouth, Reiner's pumped and scissored at a relentless pace, listening to the way Mikasa cried and moaned for more, expressing how close she was and how it felt so good. Maybe a twinge of jealousy came over Eren just then, and Reiner came off her clit and hovered over Mikasa, smirking at Eren.
"Would rather you cum on my cock." Rumbling back at her, fluttering his fingers deep and fast, right over that spongey spot that was making the woman below him a babbling mess.
"I'm sure you can make me cum twice."
And those words barely registered in Reiner's mind and how that might be an absolute blow to Eren's ego, but he didn't care, he was focused on Mikasa right now.
Moving her leg off his shoulder after bending it back into her chest, Reiner latches onto her neck, intentionally sucking hard and biting, wanting to leave a few marks so Eren wouldn't forget who fucked better.
MIkasa threw her hands around Reiner's neck and panted into his ear, clamping down on his fingers and releasing with a broken cry. Reiner smiled into her neck, giving her a few soft kisses and slowing his fingers, letting her come down nice and easy. Her smile was lazy and dazed when he came off her neck, removing his fingers and looking at Eren as he sucked them clean, a small power trip coming over Reiner then.
Eren's erection was all the more obvious now, and with Reiner's slightly inflated ego, he was going to turn him into a puddle without even touching him. Reiner flipped Mikasa over, pulling her hips up and pressing the tip of his cock to her entrance, pushing forward slowly and listening to her reactions to make sure he wasn't hurting her.
But he continued to look at Eren the entire time, placing a hand on the center of Mikasa's back to keep her pressed to the bed, bottoming out finally and letting out a satisfied groan. God she was so tight, so warm, Reiner hoped he'd last a decent amount of time for both of their sakes.
His thrusts started out slow and measured, giving her enough time to adjust to his size and to let Eren watch how his girl was falling apart on his cock already. Reiner's doesn't know where this satisfaction he was getting from watching Eren watch him, but he loved it and wasn't going to let up either.
Once Mikasa was meeting his thrusts, pushing herself back into him, Reiner pressed his chest into her back, kissing along her jaw and angling himself to hit deep. She moaned like it was the only thing she knew how to do at this point, making him throb inside her.
Eren hadn't touched himself since Reiner was keeping his vision on him, but he could tell he wanted to.
"Don't be shy Eren."
His eyes shot open, blushing red and scowling at Reiner.
Mikasa wasn't paying attention, too deep in the pleasure of Reiner's cock kissing her cervix with each thrust. But Eren still glared at Reiner, as if he were offended that the control of the situation had switched to him entirely. But Eren would admit that he was throbbing at the sight of him fucking Mikasa, making her cum and turning her into a mess, and as much as he didn't want to give Reiner the satisfaction, he knew he couldn't resist.
Eren pulled his shorts back and down enough for his cock to fly free, gripping the base and slowly moving his hand up. Eyes fluttered into the back of his head when Reiner curled a bicep around Mikasa's throat, the bulbous muscles intensifying the move so much more.
"Feel so good baby, I'd fuck you all night if you let me." Growling into Mikasa's ear with panting breaths, letting a groan rip through his throat when she raised her hips off the bed to change the angle.
She giggled and glanced back at Reiner against his bicep. "Who says you can't?"
God she sounded so assertive and in control, Reiner wished this dirty talk between them wasn't just that.
Snapping his hips and loosening the curl of his arm, he chuckled into her ear, biting the lobe. "I'll never get over the look on your face when you came, gonna have it seared into my brain when I think about you. from now on"
"Haven't cum like that before, not in a while at least."
Reiner snapped his hips again and laughed a bit deeper, moving his arm away and sitting up, pulling Mikasa's hips with him.
"You're telling me Eren hasn't made you cum like that?"
And now Eren was at full attention, irritation ever the more present, even as he lazily pumped his cock. Reiner pressed down on Mikasa's back to reform that pretty arch, holding onto her hip as he started a quick pace, moaned at how her ass bounced off his pelvis.
"Fuck Reiner."
"Has he?"
They stared at each other, Eren burning a hole into Reiner's chest as the blonde remained unfazed, bouncing his girlfriend on his cock like this was all natural to him.
"N-no."
Small clicks of disapproval came from Reiner, shaking his head and grabbing a fistful of Mikasa's ass. "Well if he wants, I can give him a few pointers, hopefully he paid attention earlier."
Grabbing both of her ass cheeks, Reiner spread them apart and buried himself deep inside her, holding himself there and realizing Eren hadn't said anything in response to all the stuff he said. Reiner would understand if he was mad, it sort of was the whole point of him saying it to begin with, but the no reaction was throwing him off.
Looking up, Reiner saw Eren was bright red and pumping his cock, almost in time with his thrusts. Now Reiner understood, giving Eren a sly smile and thrusting into his girlfriend faster and harder. He felt himself getting closer, his balls tightening every time Mikasa clenched down on him and making it impossible to focus on taunting Eren more, since he seemed to be into it at least.
"Shame you didn't end up with me, I'd be making you cum in a hundred different ways, just so I could see how pretty you look." Leaning over her back and kissing the outer shell of her ear, feeling her clench down again and giving him the sign she was close.
Directing his gaze back to Eren, he could see the man was just as close as he was, fighting it off but losing that battle terribly.
"I know you're close."
Saying into Mikasa's ear but keeping himself locked on Eren, knowing he could hear him.
"Cum for me." Grunting out, feeling himself tip over the edge right as Eren's hips shot up and Mikala's squeezed down on him again, gushing around his cock. Reiner came barely a second later, pressing his pelvis into her ass and emptying himself inside her, not having a second thought.
The room was thick with sex and unresolved tension, oddly enough not phasing Reiner as he took his time pulling out of Mikasa, letting his cock hang as his cum dripped out of her pussy. Eren sat slouched in the chair, cum coating his hand as he looked up at the ceiling. Even if Reiner wasn't feeling the slight uncomfortableness in the room, he wasn't exactly sure what he should do.
Instead of getting dressed and leaving like he kind of wanted too, he asked Mikasa where the bathroom was, grateful there was one connected to the bedroom. Reiner returned with a warm rag, cleaning the mess on his thighs and Mikasa's, rinsing it and bringing it over to Eren.
"Thanks."
Reiner nodded and stepped back towards the bed, a bit of guilt settling inside him now that his adrenaline and arousal died down, realizing all the ego bruising things he said in the heat of the moment probably wasn't the best.
"Hey, about all the stuff I said." Beginning as he grabbed his boxers.
"Nah don't worry about it."
Perplexed, taking a seat on the edge of the bed next to where Mikasa lay, Reiner gave him a look. "You sure I mean."
"Yea, heat of the moment and it's not like it affected me or anything."
Reiner wasn't buying it, but he'd leave it at that, not wanting to further hash out newly discovered kinks or actually make Eren angry when he'd let it go already.
"I'm ordering take out." Mikasa announced, sliding off the bed and grabbing the sweatshirt she had on earlier. "I can order some for you too Reiner, if you want to stay for a bit."
The offer was too tempting to turn down, so he accepted, relaying what he wanted over to Mikasa and flopping back onto the bed for a breather. Eren had left to go to the main room, Mikasa hanging back with Reiner for a moment.
"I hope you enjoyed it." Sneaking a kiss to his cheek, Reiner blushing like a schoolboy and hesitantly looking in Mikasa's direction.
"I did yea." Shyly smiling and folding his arms behind his head. She giggled and tucked some of her hair behind her ear, leaning in close to whisper instead.
"Thanks for proving my theory right."
