Approximately five days after they have the discussion, Renji goes to rut.

When an omega goes into heat, they nest. They gather soft blankets and pillows imbued with their scent and cover their bed in them. Mated omegas will gather bedding that smells like their mates too for ultimate comfort, and omegas with regular heat partners have been shown to do the same. The sight usually invokes a lot of crooning from alphas who witness this. Renji himself has been moved to softer, more delicate feelings when he sees an omega preparing for a heat cycle, the way they arrange everything with such care before they bed down for their cycle. In sharp contrast, alphas just tend to go into freak cleanliness mode.

Renji wakes up with a familiar heat prickling under his skin and drags every single piece of furniture out of his room one by one, piling them haphazardly in the hallway despite the complaints of his pack about the cramped space. He scrubs the floors clean and then dusts the walls and nearly breaks his own neck attempting to clean the ceiling. By the time Byakuya shows up in his doorway with a slightly concerned expression on his face, Renji’s hands are red from the effort and his knuckles are sore. But the room has to be clean.

“Has it started?” Byakuya asks, raising an eyebrow when Renji shoves his nightstand into its new proper place with his foot. “I suppose it has. Would you like me to help you?”

“No!” Renji winces at the volume of his own voice, his shoulders jumping up around his ears. Byakuya only looks fond and wow, that does something to him deep down in his chest. “Sorry, I didn’t mean to yell at you. No, I have to clean the room for you. Besides, I’m almost done.”

Byakuya hums thoughtfully, tucking long black locks back behind one ear, baring the slender column of his throat, and Renji thinks long and hard about the fact that Byakuya’s throat might bear his mating mark one day, that he gets to court Byakuya soon and— “Renji, are you listening to me at all? I just asked you a question.”

“Sorry, I, uh. Must have missed it.” Renji clears his throat, trying to ignore the heat building up in his face the longer he thinks about Byakuya beneath him, writhing and moaning.

“I asked you if you minded me bringing some of my bedding into your room.” Byakuya turns his eyes down and away, and Renji stalks closer to him, his instincts screaming at him to comfort the upset omega standing in front of him. “It’ll be my first time in a— Renji!”

His name leaves Byakuya’s mouth in a squeak when he sidles up in front of him, pulling Byakuya in against his chest and nuzzling the side of his neck. It’s equal parts good and mistake as he wraps his scent around Byakuya in an attempt to comfort him and inhales far too much sweet omega scent for his own good. A strangled moan leaves his lips and he feels Byakuya press into his arms, all kinds of receptive to his touch. It’s too perfect.

“So it’s like that when you’re like this.” Byakuya leans back, presses a hand against Renji’s chest. “Stop that and let go of me, and I’ll go get what I want in the room.”

“Of course. You should be comfortable here, too.” The thought of Byakuya nesting in his room is like a punch to the chest, knocking all the air from his lungs. “How’s your stomach been?”

“Unohana gave me something for the nausea, so it’s mostly stopped unless the food I’m trying to eat is heavily spiced.” Byakuya looks up at him and Renji could swoon at having those beautiful grey eyes so close to him. “So you can begin your courting whenever you wish.”

“Be rude to start it with something like sex.” Renji muses, perking when Byakuya laughs.

“After, then.” Byakuya steps back out of his arms and Renji almost chases him just to have him near and sweet-smelling and warm once more. “Finish putting your room back together and I’ll be right back. Don’t start without me or I’m going to be disappointed in you.”

As fucking if. “Alpha, I won’t.” It wouldn’t be any fun to start without him.

“You’d better not.” Byakuya smiles and leaves, and Renji moves at double the speed.

Alphas are naturally physically strong, their ability to build muscle at a much heightened level than it is for anyone else. Renji is no exception. He moves the heavy wooden furniture as if it weighs nothing, dragging it around into a better position, shoving his futon into the corner so Byakuya can nest easier there. A more secure and protective spot, and Renji can sleep with his back to the door to keep his omega safe from any possible harm.

The fact that their pack would not be out to harm them is besides the point, of course.

Rukia stops in his doorway and Renji freezes at the sight of her. “Renji, look me in the eye and do not lie to me. Are you intending to spend the next few days rutting my brother?”

“You can’t just say it like that.” Renji says, mildly scandalized at the tone of her voice.

“That’s a yes, then. Listen to me.” Rukia crosses the room in rapid strides, her hand fisting in the neck of his shirt, dragging him half bent over so he’s on a visual level with her. “I know I don’t have to tell you this, but I’m telling you this. Take care of him or I will skin you alive.”

Renji swallows and nods. Rukia smells like an incoming blizzard when she’s furious. “Of course. I was just getting my room cleaned up for him. You know you can trust me, Rukia.”

“I know that, but I’m the alpha in the family and I like getting to show off.” She pats him on the cheek and leaves him behind, suffering from the whiplash of being scolded by Byakuya’s living relative and the room still smelling slightly like her unhappiness.

This only has his pheromones heavily permeating the air around him in an effort to reclaim the space as his own. When Byakuya returns, it’ll smell like both of them.

The thought is dizzying and Renji leans against the wall for a moment. His entire body feels like it’s on fire, the physical chores only ramping his body temperature up that much more. When he picks up the scent of fresh cherry blossoms in the air, he all but bolts from his room and down the hallway where Byakuya is talking to Rukia, taking the bundled-up bedding from his arms without being asked and carrying it back to his room. Anything to take care of his omega.

“You don’t have to do that.” Byakuya calls out behind him, but it’s far too late for that.

Renji sets the bundle on the futon and waits patiently for Byakuya to join him, freezing when Byakuya steps into the room and holds out a hand, a silent command to stay still. Only when Byakuya shuts the door behind him, giving the lock a twist, does he hold out his arms. Renji all but bounds across the room to him, sweeping him off of his feet and into his arms.

“Alphas aren’t normally this unbearable when they’re in rut.” Byakuya muses. “Yoruichi never was, at least, and I doubt Rukia is. Are you sure you aren’t the one under the weather?”

“I don’t think so.” Renji says. He feels fine, at the very least. “Did you want to nest now?”

“Yes.” Byakuya pats him on the shoulder and Renji, regretfully, sets him on his feet.

While Byakuya goes about making his bed a more hospitable place— a sight that burns hot and liquid in Renji’s gut— he feels his own forehead, trying to determine if he might have a fever. He doesn’t want to think much about it, but Byakuya had a point when he said alphas normally do not act like this because they don’t. Renji himself has never acted like this before, and he used to have a regular partner to help him through his ruts. He doesn’t know what’s wrong with him.

He wonders if this is just the effect Byakuya has on him, the all-consuming hunger that grips him when he thinks about being with Byakuya. The heat they spent together was only the beginning of the end for him if this is true, and Renji licks his lips thoughtfully as he considers his options. When Byakuya has finished and seems satisfied with his nest, he sits back on his knees and pulls his shirt up and over his head, baring the perfect, lean muscled line of his torso.

All of Renji’s cognitive thought process leaks out of his ears at the sight.

“The room is very warm. I hope you don’t mind if I get comfortable.” Byakuya catches his unabashed staring and smiles softly, reaching for the waistband of his pants.

In seconds, Renji has him up off of the floor and on the futon itself, kneeling between Byakuya’s thighs as he pulls his pants down himself. “Let me help you. You’re the omega, I really should be taking care of you. Better care at least. You’re… There’s nothing under here.”

Byakuya is not wearing any underwear underneath his pants.

“So you’ve noticed.” Byakuya wets his lips and the gesture seems nervous but it’s also arousing as hell and Renji really struggles to breathe through it. “I thought it would be easier that way. If your rut came unexpectedly, you could have me whenever you wanted.”

“You’re killing me.” Renji tells him honestly, yanking the pants the rest of the way off.

Maybe he hears fabric rips. Oh well. They didn’t need the pants anyway.

The pheromones must be getting the better of Byakuya by the looks of it; he’s already flushed and swollen and wet, his inner thighs up near his vulva damp with need. Renji feels like he might just die at any moment at the sight, the heat in his body threatening a crescendo, need thrumming through his veins so hard it feels like a second pulse. And Byakuya only watches him placidly with hooded eyes, cheeks rapidly picking up a pink hue.

“You’re beautiful.” Renji leans over him, presses his palm to Byakuya’s face and kisses him as gently and carefully as he can, something in him telling him to be gentle.

When they shared Byakuya’s heat together, Renji didn’t always have to be gentle with Byakuya, could fuck him as hard as he wanted and Byakuya could take it, and gladly. But he finds himself hesitant now, something instinctual telling him to take deep breaths, take his time, and take care of the omega trusting him with this. So he slows himself down even though he wants to surge ahead, take Byakuya hard and fast until there’s nothing but sensation and pleasure. Byakuya moans softly against his mouth, curling a hand around the back of Renji’s neck and drawing him closer, wrapping one long bare leg around his waist.

Renji is wearing far too many clothes. The fact he’s wearing any clothes is proof something is wrong, very wrong, and he needs to fix it immediately.

As soon as he has his shirt off, Byakuya’s hands are there, smoothing over his abdominal muscles and the dark ink spilling across his skin. “I thought you were going to be rougher with me based on your reaction time. I suppose I was wrong in that regard.”

“I won’t be.” He leans down to capture Byakuya’s lips in a swift kiss, holding his face still as his tongue slips between soft lips to explore the warm, wet cavern behind them.

His sweatpants are gone in seconds after he stops kissing Byakuya and has to come up for air; their bodies would slot together so perfectly if he just went for it, but he doesn’t. Instead, he kisses his way down Byakuya’s body, nibbling his throat, running his tongue over pale pink nipples until they’re hard and damp from his tongue, leaving open-mouthed kisses on Byakuya’s stomach until he can feel coarse curls tickling the bottom of his chin.

Byakuya’s scent was intoxicating when he was in heat. It’s just as powerful now.

“You’re so wet.” The words rip from his throat, raw and rasping as he kneels between Byakuya’s thighs, his fingers creeping behind Byakuya’s knees, bending them and pressing them up. Winter sunlight slants in through his window, catching on his wet folds and Renji is almost sick with need and want and desire and a million other little things that all seem to center him right here, right now, between his pack alpha’s naked thighs. “I haven’t even really touched you yet.”

Byakuya swallows hard. Renji can hear the click in his throat as he spreads his legs just a little wider, one pale hand wandering down his own body to where he’s throbbing. “It’s the scent. Your scent is all over this room and I can’t do anything but react to it when you’re in rut.”

His fingers slip low to his entrance and back up, smoothing the moisture over the hood protecting his clit and Renji almost swallows his tongue at the sight. What he wants to do is chase those fingers with his tongue, suck the wetness off of them and then eat Byakuya out until he can’t feel his tongue anymore, until human speech is beyond him. Instead, he finds himself watching Byakuya, watching those nimble fingers work over his swollen folds until he’s trembling, his thighs quivering delicately as he closes in on orgasm.

“Fuck.” Renji catches him by the wrist, draws Byakuya’s hand away from himself so he can suck the wetness from his fingers, groaning at the taste of it.

“O-oh.” Byakuya watches him through eyes flickering between grey and gold, and the sight makes Renji painfully aware of just how hard he is. “Alpha, please don’t tease me.”

“I won’t.” The moment Byakuya’s fingers are clean, Renji takes a deep breath and dives down.

Omegas smell sweeter at the source but Byakuya smells intoxicating, like Renji could get hooked on his scent and his taste. The moment his lips touch Byakuya’s folds he’s moaning against them, his tongue lapping up the sweetness slicked over them, sucking them clean before he spreads them wide with his thumbs. With nothing more than the promise of this mating he’s gotten Byakuya so close to orgasm and it makes the alpha in him sit up and take notice, a pleased rumble rising in his chest, earning a soft whine from Byakuya in answer.

They were made for each other. Renji is sure of it. He hardly believes in soulmates or such nonsense but he believes that Kuchiki Byakuya was meant to be his omega.

His tongue follows the path of Byakuya’s fingers, teasing around the edge of his entrance before lapping up over his clit, hard from his own dedicated ministrations. Every inhale only fuels him on Byakuya’s scent, coating the inside of his nose and his throat so that there’s nothing but him, Renji’s entire world narrowing down to this very moment. Byakuya cries out, hips jerking against his mouth, but Renji doesn’t slow down. He just pins Byakuya down and devours him.

Every orgasm only makes Byakuya wetter, drenching Renji’s cheeks and chin.

“Renji, please.” Byakuya’s hands are in his hair, drawing Renji’s mouth away from his thighs. He’s flushed all down his chest, glistening and red between his thighs. From Renji’s mouth. “That was getting to be too much. Were you even paying attention?”

“Not as much as I should have been.” Renji slips a hand between this thighs just the same, rubbing over Byakuya’s slick folds with his fingers, breath harsh in his chest as Byakuya takes two fingers without any resistance whatsoever. “F-fuck, how many times did you come?”

“...I lost count.” Byakuya admits softly, and Renji could just. Come from that thought alone.

“Good.” Renji hauls his thighs wider apart and settles between them, pressing his fingers deeper inside of him, enjoying the way Byakuya opens up under his touch. He’s throbbing, his walls clamping down tight on Renji’s fingers. Sensitive but desperate to be filled.

Byakuya’s body is reacting to his own, picking up on what he wants and responding in kind, a compatibility that can’t be forced no matter how hard someone tries. He leans down to kiss Byakuya, whispering soft praise against his lips as he brings him to just one more orgasm with his fingers, massaging the spot just inside of him until Byakuya shakes with the force of it. The flood of wetness that comes with his climax is enough for Renji to know he can take him just like this without hurting him, without causing him any physical harm.

No matter what happens, he doesn’t want to hurt Byakuya. The thought of causing him pain twists in his gut, makes him want to vomit. He doesn’t know why it affects him so strongly, why the very thought of causing this omega pain threatens to break him from the inside out. It’s not like he’d ever want to, or want to think about doing it, but his body’s reactions seem oddly extreme. He wonders if it’s just because he happens to be in love with him.

Slowly, he lowers himself down on his forearms, pressing hungry kisses against Byakuya’s mouth as he slides his cock between Byakuya’s folds. They part around his shaft and he idly fucks Byakuya like this for a moment, not inside of him, his shaft rubbing over Byakuya’s clit until soft whines and whimpers fill the air around them. Only when Byakuya shifts impatiently up against him does he respond in kind, gripping the base of his cock and guiding the swollen head to Byakuya’s waiting entrance, sinking inside of him with a grateful groan.

Nothing has ever felt as perfect as Byakuya does around him right now.

“Fuck, baby.” He noses behind Byakuya’s ear, feeling the omega squirm against him, freezing in place. “Are you okay? I’m not hurting you, am I?”

“No. You’re going so slow. ” Byakuya bites down on his shoulder and Renji hisses, trying not to move as Byakuya’s teeth press into his skin. “You know I can take it harder than this.”

“I— I know.” He doesn’t know, however, how to explain why he wants to go slow, take it easy, treat Byakuya’s body with the utmost respect and reverence. “But I want it like this. Let me make love to you, Byakuya. You know you can trust me to take care of you.”

Byakuya nods fervently, pressing his face against the curve of Renji’s neck and shoulder. “Fine, fine, just. Please. I feel so empty can you please —”

Renji rolls his hips forward, sheathing himself inside of Byakuya’s waiting body centimeter by centimeter until the omega yowls softly against his skin. He must be so sensitive inside from Renji’s mouth and fingers that every rub of Renji’s cock is driving him insane, opening him up and teasing all of the nerves. All of his pleasure points. He throws his head back into the pillows, wild dark hair and eyes flashing gold and Renji has never been so in love in his life.

He grips Byakuya’s hips, pulling them flush against his own, letting Byakuya’s long legs wrap tight around his waist. The dig of heels into the small of his back is welcome. “Every part of my body is screaming at me to cherish you right now. I don’t know what’s going on with me.”

“I appreciate it.” Byakuya’s fingers glide through his hair, pulling him down into another kiss. “But please fuck me. Please, it’s not enough yet. Please, alpha.”

“Yes, omega.” And Renji fucks him like he means it, but with far less of an edge than he’s used to, far less of a throttle than he’s known for when he’s in rut. Every rock of his body is slow and to the point, long thrusts that have Byakuya writhing under him, twisting up and reaching for him, nails digging into his back hard enough that it hurts.

Everything around him is white noise except Byakuya beneath him and around him, his name spilling from Byakuya’s mouth in choked little whimpers while Renji fucks him slow but steady. He can feel when Byakuya’s orgasm washes over him again, can feel the pulse and squeeze around his shaft but he doesn’t slow down or stop. He just fucks into him more, listens to the way he keens as his oversensitive body struggles to keep up with Renji’s stamina. It’s just not possible, not ever but definitely not now when Renji just wants to pleasure him, to watch him fall apart until there’s nothing left but pleasure and heat and satisfaction.

“Renji, please.” Byakuya’s legs tighten around his waist as if trying to hold him still and Renji groans, grinding into him and drawing a soft cry from his lips. “Knot me, please, please. ”

How can he ever ignore such a sweet plea from such a beautiful man?

It’s an awkward position but Byakuya clings to him as his knot swells and catches on the edge of Byakuya’s entrance, wedding their bodies together. Renji slides his arms around Byakuya and holds him back, nuzzles his throat and shoulders and upper chest, stealing soft kisses from his lips. Mine mine mine pounds through him as insistently as his heartbeat, Byakuya wrapped around him so tight and sweet and perfect. This omega was meant to be his mate.