Work Text:
Diluc impatiently eyes the clock on the wall, doing his best to ignore the growing heat burning below his navel and how he’s starting to sweat under his clothes. His eyes dart back and forth from the lecture hall of students he taught to the clock, waiting for just a minute longer until the clock hand finally ticks past three and he can finally dismiss them.
Amidst the hustle and bustle, Diluc easily finds his mate amongst the horde of students eager to leave.
“Kaeya Alberich,” Diluc’s clear, low voice cuts through the white noise of chattering students. His mate, in mid-conversation with Rosaria, twitches and turns to meet Diluc’s sharp eyes.
“You’re to come to after-hours - we need to have a talk about your research paper’s proposal.”
A low “ou” spreads out and is echoed teasingly by the remainder of lingering college students. As they climb up the lecture hall stairs to leave, multiple students snigger in Kaeya’s direction. Perhaps most of the class thinks Kaeya’s in trouble with the TA, Rosaria knows better.
“Well,” Rosaria begins, eying the both of them with faint disgust. “I sure hope you two will actually use office hours like it’s supposed to be used for. And not like what you told me you two did last month.”
“Hey,” Kaeya protests. “It’s not my fault my heat came early. I swear, I was a diligent student who went in for completely innocent, school-related reasons.”
“Yeah,” Rosaria snorts. “Real innocent. So innocent you enticed him to fuck you up the wall and went at it until the school closed. Such a dedicated student.”
Kaeya shuts his mouth with a snap, face turning red. He quickly glances around, but luckily the students are almost gone and it’s just the two of them in their side of the room. “What if someone hears?” he hisses.
“What. It’s not like you’d mind since you’re so freely sharing your sex life with me.” Rosaria smirks. She stands up, tucking the chair back into the table. “Have fun with your lover boy, whore.” She turns to leave but pauses to fix a firm glance back at Kaeya. “Oh, I know you two are probably going to fuck, but for the love of god don’t you dare text me about the details again.”
Kaeya grins, leaning back in his chair. “You said no texting...so calling’s fine, then?”
Rosaria sighs but doesn’t bother replying. She turns her back to Kaeya, hitches her designer bag further up her shoulder, and gives him the middle finger as she saunters off - the sharp, long, silver acrylic nail resting on her middle finger fiercely glinting under the artificial lights.
Kaeya watches as the heavy doors swing shut behind her. He hears Diluc’s footsteps, light but purposeful, striding up the stairs and turns to face his mate. His bond tingles and he feels himself relaxing the closer his mate gets. He tilts his head up to view Diluc above him, inhaling the comforting scent of wine and lampgrass. He greets his lover with a mischievous grin, dragging Diluc down for a peck. “So,” he purrs. “What naughty things did I do for you to call me out today, teach?”
Diluc sighs. Kaeya waits for the usual no-nonsense attitude from Diluc, searching his lover’s gaze. What he doesn’t expect is for Diluc to lean down and nuzzle the side of Kaeya’s neck, rubbing his scent over Kaeya’s scent glands. Kaeya flinches at Diluc’s hotter-than-normal body temperature.
Kaeya twists to grasp Diluc’s face down to his level, cradling Diluc’s almost feverish-like face between his hands. “What’s wrong?”
Diluc sighs gratefully, no doubt relishing the cold relief Kaeya’s palms bring. “I’m in my pre-rut and I need your help, Kaeya.”
Kaeya pauses. “Er. Now? Not that I don’t want to help you, but I actually have class in two hours…”
Diluc’s eyes close and he leans his weight into Kaeya’s hold. “The office is open; Professor’s on vacation, remember?” he murmurs. “I promise I’ll restrain myself enough so that you can make it to your next class.” Diluc reaches to grasp Kaeya’s wrists, opening his eyes to hold Kaeya’s gaze. “Kaeya. Please.”
Kaeya’s breath hitches. Diluc never begs - so for him to ask Kaeya of this shows how unbearable it must be getting for him. “All right, all right. Anything for you.”
Diluc rumbles out a sound reminiscent of a purr, no doubt pleased that he managed to convince Kaeya. He leans in close, breathing in the scent of his mate’s pheromones and only separates himself after one last nuzzle to Kaeya’s scent glands.
Diluc waits for him by the stairs, and when Kaeya approaches, he wordlessly holds Kaeya’s heavy bag without being prompted like the gentleman he is.
The two walk as calmly as they can towards the building designated for Diluc’s professor as to not to draw suspicion, then quickly power walk the rest of the way to the office. The two take time to take off their shoes - mainly Diluc, because his oxfords need to be loosened and can’t just be kicked off like Kaeya’s boots can. But as soon as Diluc locks the office door, he becomes anything but a gentleman.
It’s rather dim in the weakly-lit office with the light faintly spilling out behind closed curtains and the lights off, but that doesn’t deter Diluc. He drops their bags hastily in favour of pushing Kaeya down onto the desk, his hands fumbling to unzip Kaeya’s skinny, black jeans.
Kaeya lies flat on the desk, and when he feels Diluc sliding his hand underneath to massage at both his cock and folds, he tilts his head back with a heavy exhale. He feels himself harden under Diluc’s attention, slick trickling steadily out of him to coat Diluc’s fingers and easing the slide, making everything more pleasurable. Distantly, past the building pleasure, he can smell the way his pheromones thicken in the air, the scent of frost and calla lilies spreading to fill the room. He feels Diluc hum appreciatively under his chin, slowly loosening his own hold on his pheromones so that both of their scents can mingle in the air.
“So wet for me,” Diluc praises in between gnawing at Kaeya’s scent glands. Kaeya hums, then jerks as one of Diluc’s fingers (long, slender, the perfect size-) slides in. At the same time, Diluc bites their bond mark, causing Kaeya to gasp and involuntarily clench down on Diluc’s finger.
“Alpha,” Kaeya keens, tilting his pelvis up to try to get Diluc’s fingers up farther up inside him. The scent of Diluc’s pheromones mingling with his is starting to make his thoughts hazy. It’s as if Diluc’s pre-rut is making him go into heat. “Want to be good. Just for you, just for you.”
In lieu of a reply, Diluc slides in two more fingers with his index finger. Kaeya leaks out more slick, helping Diluc stretch him out further.
“More, more, more,” Kaeya chants, canting his hips around to get Diluc to brush against that particular spot within him. Diluc chuckles, and it takes Kaeya a few seconds before he realizes he’s clenching down on nothing. Kaeya groans, snapping his eyes open. He’s more than prepared to chew Diluc out for being a tease, but when he sees Diluc raising his fingers to his mouth, his mouth goes dry.
Mesmerized, he watches Diluc lap at his fingers. He licks the slick off them with an almost laughable amount of elegance (it’s the young master in him, for sure) for the obscene act he’s doing, but that somehow makes it all the hotter for Kaeya. Diluc smiles knowingly at Kaeya like he can read his thoughts, holding his lover’s gaze as he uses the tip of his tongue to daintily lick the slick off his fingers. Kaeya watches greedily, licking his lips. Pinned under the weight of Diluc’s fiery gaze, he feels himself start to throb with want, slick pooling underneath him, as he stares - hypnotized by the way Diluc swirls his tongue around his fingers, the way Diluc breaks off to lick his lips then goes down on them - swallowing them and bobbing his head up and down, only popping off when most of the slick is gone. Kaeya stares at the way his slick gives Diluc’s lips a sheen, his eyes focusing on the way the string of saliva connects Diluc’s pretty, red mouth to his long, elegant fingers.
Suddenly, nothing else feels more important than wanting to feel that talented mouth against his own. Kaeya lunges forward to drag Diluc down in a kiss. He hits the table a bit hard but finds himself hardly bothered, moaning as he tastes his own slick on Diluc’s tongue.
Diluc kisses Kaeya back like he’s starving. He devours Kaeya’s mouth, sucking on his lover’s tongue and gnawing on his lips like he wants to eat Kaeya whole. The two make out sloppily, all the while with Diluc rubbing his hips incessantly against Kaeya.
“Want you,” Diluc growls in between kisses. “Need you. Such a sweet-tasting omega. You taste so sweet, my Kaeya. My omega.”
“Mmhm,” Kaeya pants out. “Only for you, alpha.” He paws at Diluc, pulling at Diluc’s blouse. “More, alpha. Give me more.”
Diluc breaks the kiss, pressing a deceptively sweet kiss to the corner of Kaeya’s mouth as if he hadn’t just tried sucking Kaeya’s soul out of his mouth. “Always so good for me,” Diluc praises. “If my omega wants more, then how can I refuse?”
Still pressing kisses, but this time trailing from Kaeya’s lips down to his neck, Diluc blindly fumbles around before finally succeeding in shoving down Kaeya’s pants. Kaeya wiggles, the two reluctantly breaking apart to help discard Kaeya’s jeans into a random spot in the room.
“Off,” Kaeya demands as he tugs off his own shirt and tosses it away. He sits, now fully naked except his socks, watching Diluc carefully unbutton his black blouse to reveal the slender, pale body beneath. Kaeya continues watching, slick trickling from him to pool under the table, as Diluc takes the frustratingly longer-than-necessary time to carefully slide the blouse off himself, muscles rippling as he does so, to hang it over the back of the chair.
“As much as I enjoy this sexy strip show, Diluc, can we just get to the fucking part already?” Kaeya huffs. “A wrinkle or two in your clothes won’t hurt you, you know.”
Diluc doesn’t glance up from his current task of unbuckling his pants and stepping out of them as he replies with, “Patience.”
Kaeya snorts. He waits, impatiently, and as soon as Diluc lays the pants over the back of the chair with the blouse, he immediately draws Diluc back down on the table with him, relishing the skin-on-skin contact and the familiar weight of his alpha on top of him.
They make out lazily. Their hands roam, feeling each other up, fingers pressing onto familiar bruises made from the sex they had earlier this morning. “I want to taste you,” Diluc whispers as he breaks off.
Kaeya spreads his legs wider in response, grinning.
Diluc grasps Kaeya’s cock and gives it a few lingering strokes before he takes it within his mouth. He pushes Kaeya’s thighs out wider, the other hand reaching down to finger Kaeya, his three fingers sliding in more smoothly than earlier thanks to the steady slick dripping out from Kaeya’s pussy.
Kaeya whines at the feeling. The way Diluc’s hot mouth engulfs his shaft, from the way Diluc hollows out his mouth and sucks, and from the feeling of Diluc’s fingers stretching him wide open for his cock – all of it feels too good. When Diluc begins bobbing his head up and down, popping off occasionally to tease his head or blow air onto the cooling saliva coating Kaeya’s cock, Kaeya lets out a loud moan. His fingers grapple around, wildly searching for an anchor, before clinging on for dear life to the sides of the oak desk. Diluc doesn’t relent, swirling his tongue around, paying special attention to the foreskin near the head. He takes out his fingers when he moves to eat out Kaeya’s pussy.
“Oh, Archons,” Kaeya whimpers, belly tensing and thighs buckling, as Diluc licks between his folds and starts slurping the slick out from within him. His tongue circles around, licking inside shallowly at first then deep, as he sticks his tongue in deep to fuck Kaeya. He ends with a harsh suck, slurping the slick out within Kaeya.
Kaeya jerks his hand up to his mouth to muffle his scream, writhing against Diluc’s grip. On instinct, he tries to close his thighs against the overwhelming pleasure and bucks back, but Diluc’s grip is strong, and he doesn’t give Kaeya time to catch his breath, keeping Kaeya in place and spreading his thighs out wide.
“Such a sweet omega for me,” Diluc praises and then, without pausing in mouthing around his folds, slides four fingers in and scissors them around, stretching Kaeya out so he can take his cock and knot. Diluc glances up as he does so, loving the way Kaeya’s face scrunches up in reaction to that familiar pleasure-pain of the sudden stretch. He watches with a primal sort of pleasure, the alpha within him in delight over the way his mate shows his pleasure - the way Kaeya throws his head back and keens against his hand. Kaeya, no doubt, loves the way Diluc’s cock carves him open. He clamps down incessantly around Diluc’s fingers and twitches against Diluc’s tongue. Diluc and his alpha side both rumble happily at this, loving the way Kaeya is driven insane with pleasure.
Diluc dives back and eats Kaeya out with a renewed vigour, wanting to melt down all of Kaeya’s inhibitions until he has Kaeya wailing from how good it feels – passersby be damned. He reaches in deeper and stretches Kaeya out wider, each time massaging against that spot in Kaeya that has his beloved jerking up with a loud moan, writhing.
“I- Diluc,” Kaeya gasps out, body tensing. “I’m gonna - no more, no more. Want you in me - don’t make me come yet-” He cuts off with another moan that ends with a loud keen as Diluc obeys, removing his hand and, with the flat of his tongue, licks all the way up back to the head of his cock and pulls off.
Before either of them can catch their breath, Diluc’s standing up and hoisting Kaeya’s legs up in the air so that he’s presenting all of himself to his mate.
“I think you’re ready, no?” Diluc says, pressing a quick kiss to Kaeya’s calf. “I can’t wait anymore.” He eyes Kaeya, his pupils blown wide and mouth shiny and red with slick.
Kaeya clenches down against the rush of slick that floods out from within him at that, from how hot his mate looks, and feels his cock ache and pussy throb at the promise of what’s to come.
“You stretched me out so good – fucked me so well with your mouth,” Kaeya purrs out as best as he can, still struggling to catch his breath. He inhales, then smirks, baring their bond mark in an unspoken invitation that has Diluc’s eyes darkening with lust. “Do your worst, alpha.”
Unexpectedly, Diluc smiles at that. It’s a soft, loving smile, but it contrasts deeply with the darkening lust bleeding from his eyes. Diluc’s expression makes Kaeya shiver in anticipation.
“I can’t be held accountable if you can’t walk straight after this,” Diluc says, adjusting Kaeya’s legs so that one rests on his shoulder while the other is spread out wide.
Kaeya laughs, tilting his head in a way that he knows drives his lover wild, and bats his eye up at his alpha with a saccharine smile. “Is that a threat? That everyone would know teaching assistant Diluc held me up after class to screw me? That he fucked me like the slut I am, bent me over the desk, made me his bitch and fucked me until I cried?”
Diluc snorts. Used to Kaeya’s teasing and big mouth, he doesn’t reply and instead aligns himself, teasing Kaeya back by shallowly pressing in and out, before finally guiding himself in with a push after Kaeya’s whines of displeasure.
The loud, wet squelch in the room is quickly overshadowed by both of their groans. Kaeya tenses as Diluc eases himself to about halfway in. The stretch is obscene, even with the ridiculous amount of slick he’s leaking, but the ache is soon forgotten in the wake of satisfaction he feels about finally being filled just the way he wanted. Diluc is both wide and long, and the way he forcibly carves into Kaeya even though they fucked earlier this morning before school has Kaeya moaning from both the sensation and the thought of how hot it is how well-endowed his alpha is. And the knot to come – the way he’ll be stretched wider and filled more as Diluc’s come is plugged in has Kaeya positively salivating.
“Are you okay?” Diluc whispers hoarsely. Kaeya looks up, seeing the way Diluc has paused, temples beaded with sweat and hands shaking in their grasp at Kaeya’s legs. A rush of warmth fills him, and he feels a fond smile unfurl across his face. That’s his Diluc - even when pre-rut threatens to overwhelm him, he’s still ever the gentleman – waiting for Kaeya to give him the green light before proceeding all the way. Kaeya stretches out his arm to caress Diluc’s face, surprising Diluc into blinking his eyes opened from where they were clenched shut.
“You can shove it all in, you know,” Kaeya whispers. “I can take you. No matter what you give me. Promise.” He shifts forward, trying to lean a bit closer to Diluc so he doesn’t miss Diluc’s reactions to his next words. After all, he wouldn’t want to miss the way his darling, strait-laced lover flushes beautifully upon hearing his dirty talk. “After all, you know how much of a slut I am for your cock, don’t you, Diluc? I want it in me all the time, stretching me full, carving me open - pounding into me like I’m your cocksleeve until I’m flooded with your come and bred like the whore I a-”
Diluc growls, highly embarrassed, and Kaeya enjoys how his mate predictably flushes a bright red from his ears to his neck.
Unfortunately, Diluc doesn’t give him much time to admire his work when he slams himself inside. In response, Kaeya clenches down, but that does nothing to hinder the way how Diluc’s cock forcefully shoves its way up into Kaeya, the sheathed cock hard and burning hot inside him. The force and speed of Diluc’s thrusts push out all the air from his lungs and whites out all thoughts from Kaeya. He comes, mouth opening around a loud, broken gasp; body jerking and clenching down incessantly. Distantly, past the blood rushing to his ears, he hears Diluc moan in response to the orgasm taking hold of Kaeya. It takes him a while to come back, and when he does, he finds himself weakly meeting Diluc’s kisses with his own. He slowly loosens his grip on the desk and, instead, searches for Diluc’s hand so he can interlock them together.
It takes several deep breaths and both of them eventually lose the kiss to just moan and breathe each other in. Kaeya feels overly full, his walls fluttering around Diluc as he’s still sensitive from his previous orgasm. It’s not until Diluc nuzzles his neck, layering his own scent thickly onto him, that Kaeya begins to feel more like himself.
Kaeya inhales and tentatively clenches down, drawing out a low moan from both him and Diluc. Kaeya’s skin tingles. Diluc feels too much, but Kaeya absolutely loves the pleasure pain that comes with having sex with Diluc’s monstrous cock. He rocks himself back into Diluc slowly, chuckling at how wetly it squelches from where they’re connected. Diluc holds still, letting Kaeya fuck himself gingerly back onto his cock, continuing to scent Kaeya to soothe him.
Eventually, Kaeya builds up the pace. He turns his head to lean against Diluc’s temple, breathing in Diluc’s scent, exhaling in a moan. He feels like Diluc’s dick is so far up in him that it reaches the back of his throat, and it’s great. Kaeya might be oversensitive, but that’s perfect. And Kaeya wants to feel this sensation even more.
“D-Diluc,” he begs. His voice cracks, but he finds he can’t care less if he loses his voice. All he can focus on is his alpha - the red of his eyes, the pretty flush spreading on his pale skin, the way his scent blends so good with his. The way Diluc gazes back at him, eyes hungry, hair messy, sweat beading down his forehead. Kaeya clenches down and watches the way Diluc closes his eyes, lost in the sensation, the way his beautiful lips open around a groan. “Fuck me hard, alpha. Please.”
Diluc inhales, presses his forehead down onto Kaeya’s shoulder, breathing in Kaeya’s scent to steel himself, before he heaves himself back up. He drags himself out slowly to give them both time to adjust, before thrusting back in at the same, careful pace.
Kaeya takes deep breaths, trying to match the rhythm of his breathing to Diluc’s thrusts, and finds it working with limited success. As the thrusts gradually increase in pace, Kaeya eventually just lets go. He focuses on the white-hot ball of pleasure kindling within him – the delicious friction from the way Diluc’s fat cock slides into him just right, the way Diluc’s knot grows in size and kisses his rim – occasionally shallowly entering in with Diluc’s cock, the way his own cock bounces and slaps his stomach from the force of Diluc’s thrusts. Past the hazy pleasure clouding his mind, he hears the wet squelches and how Diluc forces out gasps, pleas, and moans from him. Diluc moans, too, softly, as his hips rut incessantly into Kaeya.
Kaeya tightens his legs around Diluc to draw his alpha in closer – deeper - the best he can. Eyes clenched, he leans his head back, the untouched surface of the desk a nice, cool relief to his hot body. He tries to muffle the obscene sounds spilling out of his mouth but, honestly, he cannot bring himself to be quieter. Diluc himself is lenient with voicing his pleasure - either too lost in pleasure and pre-rut haze clouding his judgement, or he just simply doesn’t care if the scandalous way they’re using office hours might be heard from passersby.
Somewhere along the way, Kaeya’s legs grow limp, and it slips off Diluc’s shoulder to dangle in the crook of Diluc’s elbow. Diluc lets it dangle, mind only able to focus on chasing the pleasure burning beneath his navel.
“Kaeya,” Diluc groans, mouth pressed on Kaeya’s neck near their mating bite. He kisses it occasionally, when he has the breath to, and Kaeya shivers from both the mumbled praises spilling out Diluc’s mouth and the sensitivity of having his mating bond touched by his alpha while his alpha is fucking him so good.
“Alpha,” Kaeya whimpers out. “You fuck me so good, alpha.” He rocks back to meet Diluc in the middle, squeezing down, trying to take Diluc in deeper with each thrust. Each time, it gets harder and harder to do so with the swelling of Diluc’s knot, but with Diluc’s stamina and Kaeya’s persistence, their pace has yet to drop. Kaeya relishes in the way Diluc carves him open, the way he pushes in with deep, unfaltering thrusts to hit that spot deep inside him - the one that whites out Kaeya’s vision half the time even though he just came. “Want to be g-good for you, alpha. Only you, only you.”
Kaeya feels the way Diluc’s lips smile across his skin, and both himself and the omega side within him delight in getting their usually stoic mate to be pleased with how good he is for his alpha.
“The best,” Diluc agrees. The pace at which he slams into Kaeya increases brutally, the knot forcing itself in more and more, and just before Kaeya can’t take any more pleasure, Diluc pushes all of himself inside, sealing his knot in to lock them together at the same time he bites their bond mark. Kaeya seizes from the overwhelming sensations, crashing over the edge and crushing Diluc’s fingers in his grip as he comes with a wail. Diluc follows suit with a moan, spilling his seed deep within Kaeya. As Kaeya recovers from the aftershocks, he feels how Diluc keeps coming within Kaeya, spilling into him in hot, pulsing gushes that plug him up until he’s unbearably full and then some – the knot making sure nothing is spilled out and offering him no reprieve.
“Fuck,” Kaeya pants. Diluc’s done coming, but the knot will take a long while before it goes down. He looks down between them to see the way how Diluc’s cock and come creates a large, protruding bulge in his stomach.
Diluc hums in agreement, kissing their bond mark. “The best omega,” he whispers lovingly – something that has Kaeya shivering in delight from the praise. He then reaches down to press down at the bulge on Kaeya’s stomach as he shallowly ruts up. Kaeya immediately gasps and keens from oversensitivity. Diluc’s cock feels like it hasn’t softened one bit.
“I’m- too much, too much,” Kaeya whimpers out, feeling like he’s going to tip off the edge again. “Diluc. Please.”
Diluc hums noncommittally. He loosens his hands out from Kaeya’s sweaty clutch, moving both hands to cradle Kaeya’s ribcage. Diluc’s thumbs circle around his areola before toying with his nipples. At the same time, Diluc chooses to circle his hips, grinding around as best as he can, threatening to pull out from Kaeya’s walls. For Kaeya, who feels hypersensitive and thrives on the pleasure-pain Diluc gives him, it’s too much. He inhales sharply and comes again with a whimper.
Diluc hisses at the way Kaeya tightens around him but keeps grinding his hips up into Kaeya’s. When Kaeya calms down, panting heavily, Diluc doesn’t relent. He leans down to kiss their bond mark, tonguing the sensitive gland in a way that has Kaeya seizing up again.
“Remember. You promised me two hours until your next class.”
Kaeya whimpers in response. “Diluc, please. Spare your poor, fucked-out omega.”
Diluc snorts. One hand pinches Kaeya’s nipple harshly. Ignoring Kaeya’s yelp, he grinds up hard against Kaeya, making Kaeya cry out when his oversensitive, softening cock grinds up into Diluc’s abs. “It’s barely been thirty minutes, Mr. Alberich.” Diluc levels down a hungry glare, smirking when he sees Kaeya gulp.
“It’ll be in your best interest to keep up with the pace of this session,” Diluc emphasizes this by grinding down until Kaeya sees stars. “After all, I don’t go easy.”
Kaeya moans feebly in response. He’s definitely not going to be able to walk after this session.