They spend most of the first day indulging in countless rounds of sex, Byakuya’s head fuzzy, unable to grasp the passage of time. He snaps at Renji every time Renji makes him take a break for food and water even though he can tell how desperate his body is for nourishment, not used to being pushed so hard and in such a state. Byakuya is a skilled fighter with more stamina and prowess than most, had climbed to the status of pack alpha after killing the man to hold the position before him, but his body is exhausted from the sudden heat after so many years of nothing, and Renji keeps him on the edge of passing out.

By the time evening falls, Byakuya can hardly move. He isn’t sore, Renji has been careful with him the entire time, always making sure he’s prepared no matter what they do together. Despite Byakuya’s best attempts to keep them both going, Renji makes him stop and rest. He’ll have to thank Renji for that in a sincere fashion when everything is over, though he doesn’t know how he can go on doing this a second day, much less any more. It makes him wonder just how much destruction this heat would have wreaked if there was no one else to help him keep it in check.

Renji, in contrast, seems relatively fine. Byakuya knows his pack beta has an astounding amount of stamina as well, but the fact he can walk so easily across the room to close the curtains, hiding the evening sky and all of its stars from view, makes Byakuya distinctly jealous. Holding himself in a sitting position takes more effort than he thinks he has right now, but he does it stubbornly just the same. When Renji glances over his shoulder in Byakuya’s direction with a soft smile, Byakuya tries not to let it show on his face how fond he feels right now.

Byakuya would never consider anyone in his life to be particularly close to him, but Renji has been someone he can trust. He expected Renji to fight him for his position shortly after coming to stand at his side, but as the years passed and Renji attempted no such thing, Byakuya began trusting him with more pack matters, treating him like a second-in-command rather than someone who might soon stab him in the back— and rightfully so, it’s the way of things. Now would be an optimum time to take his place, when he’s too weak to fight back and his shields are lowered, but Renji only comes to sit next to him in the nest, stroking a hand down his face.

“Your skin’s still warm, but it’s not as bad as it was when I showed up this morning.” Renji sounds pleased with that, fingers slipping under Byakuya’s chin, ghosting down his throat. “I’m glad. Getting overheated wasn’t going to make this easier on either of us.”

Byakuya’s eyes drift shut at the gentle pressure of Renji’s fingers on his skin. “I wasn’t aware of such a thing could occur, but then, it’s been a very long time.”

“It’s not supposed to be a thing that can occur, actually. Overheat would only happen if you did absolutely nothing to soothe it yourself, not even with your own hands. You should have.” Renji’s voice, with that note of disapproval, rubs Byakuya the wrong way. His stomach feels funny at the sound and the smallest whine threatens to rise in his throat. “But we got you down, so it’ll be manageable from here on out. C’mere, I’m going to carry you to the bath.”

“The only reason I’m allowing you to carry me is because you’ve thoroughly tired out my legs.” Byakuya forces his eyes open, swallows down the sound in his throat.

Renji chuckles and kisses the side of his head, the small sign of affection making him melt. “Of course. My bad. Even doing it for your sake, I got a little excited and went overboard.”

Byakuya curls his arms around Renji’s shoulders, sighing softly when Renji picks him up, an arm braced around his back and another beneath his knees. Logically speaking, there is nothing about being held close to Renji’s chest that should make him feel safe and protected, but he knows the heat and his own base omega instincts are winning out over common sense and logic right now when his body is so worn out and he needs the assistance. Renji has been taking care of him all day besides that, so of course his body responds so well to him.

“You’re warm.” Renji murmurs, but the tone of his voice is different, less making an obvious observation and saying something softer, something Byakuya does not quite understand.

“Of course I am.” Byakuya tucks his face against the side of Renji’s throat where his scent is strongest, comforted by the closeness. “I’m in heat, Renji.”

Renji chuckles. “Yeah, yeah, I know, Tai— Byakuya. Let’s get you in the bath so you can sleep.”

The bathroom is warm and humid when Renji crosses the threshold and Byakuya lifts his head to see exactly why. The tub is already full of hot water, the surface milky, visible bubbles floating on top of its surface. Lavender floats through the air and Byakuya needs only tilt his head slightly to realize the scent comes from the water, the essence added to the bath and allowed to permeate the entire pool before their arrival.

“You shouldn’t have added something to the water without asking me first.” he mutters.

“Why did I think you’d let even this one small thing go when I know better?” Renji closes the door with his foot, then carries Byakuya over to the bath. “Lavender will relax you and help you sleep. Do you want what happened last night to happen again tonight?”

The memory of the heat that seemed to consume his skin and refused to let him so much as close his eyes makes Byakuya shudder all over. “No, I suppose I don’t.”

“Not that it could. If you woke up in the middle of the night, I’d be there to take care of you. But it doesn’t hurt to play it safe. Besides, lavender and cherry blossom smells nice together.” Renji has to lower himself to his knees in order to set Byakuya in the water, as careful as always.

The water is at the perfect temperature, warm enough to be pleasant while not being so hot that it threatens to overheat Byakuya’s body more than it already has been today. The lavender that wafts up to his nose is a pleasing scent and he sighs as he allows himself to sink into the water, his body welcoming the comfort. For a moment, he loses Renji’s scent and he tilts his head, watching Renji sit carefully on the edge of the tub, obviously placing himself within reach should Byakuya need anything. While the consideration is admirable, Byakuya wants more than that. He stretches out a hand, wet fingers sliding down Renji’s arm.

“Come into the bath with me.” he murmurs.

Renji cocks his head. “You sure, Byakuya? I’m good with just waiting.”

“I want you in the bath with me.” The subtle change in wording has Renji’s eyes softened, his body already moving forward. “Having you close to me is more pleasing than just the bath.”

There is no hesitation in Renji’s movements now. He slides into the water and pulls Byakuya’s back against his chest, arms settling around his waist, keeping him as near as he wants to be. Byakuya sighs blissfully. The touch combined with the warmth of the water, and lavender is a perfect storm to finally give him a moment of relaxation. While the day has been a long one for both of them, this is a perfect way to end it. Byakuya can only imagine how an evening of sleep will feel after this, and an evening of sleep with Renji at that.

“See? It’s good, isn’t it?” Renji scoops up a handful of water, dribbles it over Byakuya’s bare shoulder. The droplets roll over his skin before rejoining the bath water.

Byakuya tilts his head back, letting it fall against Renji’s shoulder. “Just this once, I take back my criticism from earlier. You were correct to make this choice for me. Still, ask next time.”

“I will.” Renji nuzzles against his cheek and Byakuya purrs softly. “For now, rest.”

Byakuya closes his eyes, letting himself relax in Renji’s arms, allowing the mingling scents in the air and the comforting warmth around him to lure him into a sleepy state. He has no idea how much time passes like this, too sated to think about moving, too comfortable. Renji’s slow, soft and easy breathing against his back is a reassurance, as are the arms around his waist. Byakuya can almost understand how some of the members of his pack were able to move on from sharp loss in order to seek this bond out once more. It might not ever be something he wants, but he can slowly wrap his mind around it like this.

Two people wrapped in each other, breathing in sync, two hearts beating as one.

“Should probably get you into bed soon.” Renji murmurs in his ear, and Byakuya whines at the intrusion. “Shh, don’t be upset with me. I’ll even wash your hair for you.”

“You’re the one who got me dirty. You should wash all of me.” Byakuya mutters.

Renji kisses behind his ear, hands sliding up his stomach. “I can do that for you.”

It was a joke but Byakuya doesn’t argue when Renji’s hands slide into his hair, tipping his head back enough to soak the strands to the roots. Though Byakuya prides himself on being an omega who can take care of himself and desires no one to do it for him, there’s something pleasant about all of this. Renji’s hands are strong and capable on his body, touching him with a reverence not lost on Byakuya even with how tired he is. Renji has already respected him as his pack alpha and as a person, so it only makes sense such respect would bleed into something as simple as washing Byakuya up after the strenuous day they shared together.

None of the soaps Renji uses are ones Byakuya would have chosen for himself. They all carry floral scents that will mesh naturally with his own, and he can only imagine Renji in here, picking out each one to suit his scent best. If it was any other situation, Byakuya would argue with him about making choices without asking, but most omegas do this in heat, seeking out scents to make theirs all the more alluring to entrance their partner. Renji assumed based on logic.

If it makes the experience more pleasant for him, then so be it. Byakuya will allow this because Renji is his heat partner, so if he wants to perfume Byakuya in such a way that his scent becomes all the more overwhelming, that is his decision.

“It’s been a long time since I’ve taken care of an omega. You don’t make it easy.” Renji’s voice is light and teasing, but the words catch Byakuya’s attention just the same. He glances over his shoulder at Renji, whose hands are currently focused on washing his back— and massaging the nonexistent tension from it, apparently.

“A long time?” He questions. “Did you have a mate before you joined the pack, or do you regularly offer your services as a heat partner to others?”

Renji stops moving, eyebrows raised. “Why do you ask? Does it matter to you?”

Does it matter to me? I asked… But why? “Of course not. Why would it? I was just curious.”

“If you say so.” Something in Renji’s tone suggests he does not quite believe that, but he also does not broach that topic. “I was someone’s heat partner in my old pack, and she was my partner when I was in rut. But we were only friends. It’s not something I see a lot of in your pack, so I was surprised when you came to me to ask for my assistance.”

Byakuya presses his lips together thoughtfully. He’d never thought about it that way before. “Well, I don’t ask about the personal affairs of most of my pack, so I wouldn’t know. However, before meeting Hisana, I had a companion who performed such a task for me.”

“Surprised you didn’t ask him instead.” Renji muses.

“My former partner has a mate now.” Byakuya says softly. “I wouldn’t intrude on such a bond. After all, I know how sacred a bond like that is, and what it means to lose it.”

Renji’s arms tighten around him in a moment’s notice, Renji’s back pressed against his nose, nose pressed into his hair. It’s such an immediate reaction that it takes Byakuya a moment to process what he’s reacting to. The creeping pain easing its way into Byakuya’s chest, tempting to pull him down when he’s already in such a vulnerable state. His hands move to grasp Renji’s wrists, his back pressing tighter against Renji’s chest so he has an anchor against that pain. He’s not willing to go back down that path. Hisana is gone. She’s been gone. There is no need to let himself linger on the memories of the past.

“I’m sorry for even bringing any of this up.” Renji whispers against his ear.

“You didn’t. I was the one who pressed the matter, and that led us here.” Byakuya forces himself to uncurl when he realizes his shoulders are starting to hunch. He will not show any signs of weakness. “I apologize. I’m fine, but thank you for considering me.”

Renji huffs against his cheek. “Don’t you dare thank me for that. It’s the bare minimum a person should do. You’re a good person for not going to your old partner and getting involved in their relationship. But there’s no toes to step on with me, so… It’s early to bring this up, maybe, but if you decide not to go back on suppressants at all, I can be your regular partner.”

“What makes you bring that up at all?” Byakuya asks, trying to ignore the way his stomach tightens at the thought. This, a regular occurrence?

“If you go back on them, you’ll have to take regular breaks from them anyway. You said you didn’t want to make infertility a certainty.” Renji shrugs. Byakuya can feel the shape of it against his back. “We still have got days to go, so I’m putting this on the table so you have time to think about it. I won’t make it so that you have to be my partner when I’m in rut, though.”

Byakuya nods slowly, letting the words sink in. Having a regular partner for his heats would be easier than finding a different one every time, but he’d been under the thought process he would go back on suppressants. Logically, he knows his next heat will hardly be so explosive, but no part of him is eager to endure this again. The next heat will be easier, more akin to a regular cycle as his body will have time to process. Having Renji as a partner would make it easier to bear because Renji has taken excellent care of him so far. Byakuya has no reason to doubt him.

He knows of only a handful of packs where the alpha and beta, rather than being in constant competition with one another, share their cycles together in order to show the pack that they trust one another. If Renji never intends on taking the alpha position from him— and he seems like he doesn’t want to— it might be a decent thought for the future. He should ask Yoruichi what she’s heard about the two of them and if she thinks it might be something that could work in a realistic sense. After all, she brought it up when she was teasing him.

“I’ll think about it.” he finally agrees, ignoring the way Renji hums in approval against his neck, the way it makes him weak. “I’m tired now. I would like to go to bed.”

“Of course. Sorry for keeping you up so late, but I thought the bath would be good for you.” Renji slips out of the water, Byakuya surprised at how keenly he feels the loss.

But Renji is there a moment later, helping him out of the water, helping him dry off before carrying him back to the bedroom. Byakuya lets himself be set at his kotetsu while Renji changes the bedding for him. They’d ruined the sheets already and Byakuya has a feeling they’ll go through a set every single day at this rate, especially if this pace is kept up. It’s embarrassing to think about even if it is par for the course.

Renji lets him reassemble the nest before helping him back into it, letting Byakuya pull him in and arrange him as he wants. The pillows still smell of Renji so that his scent wraps around Byakuya more securely than the blanket does, and he can sense the distinct pleasure in that scent. He hates that it affects him so much, that it makes him feel better to know he’s done something to please Renji in one way or another. It’s not his purpose in life.

He wonders how others can endure it. Hisana was a beta, not an alpha, and her scent had always been mild, not something Byakuya noticed shifting often until she fell ill and death was near. Yoruichi’s scent was none of his concern even when they were, well… Because they were friends, and that was obvious to him even then, and then Urahara had come along and Byakuya never had to worry about it ever again. He’s learned to analyze the scents of alphas in his pack, but only insofar as to read the moment they get annoyed when he puts them in place.

“Remember.” Renji says, knocking him out of his thoughts, “If you wake up in the middle of the night and you need me, wake me up. Do not hesitate. I’ll be upset if I wake up and you’ve been suffering for hours rather than if you just wake me up at like, four in the morning.”

Byakuya frowns up at him. “I don’t see why. Isn’t being woken suddenly more jarring?”

“No— Byakuya, listen to me. I am here to take care of you. I’m not just doing this for you, okay? And I’ve got my own pride as an alpha, too. I want to take care of you.” Renji leans away to look down at him, their eyes locking and a small sizzle running down Byakuya’s spine at the contact. “You came to me to ask me to help you through this. You’re my pack alpha and I respect you so much, and I know it’s been… Hard for you. So if I could help, I wanted to. I didn’t come here just to sit back and watch you suffer when your heat gets unbearable for you.”

The sudden outburst has Byakuya running his teeth over his lower lip, not sure how to respond right away. But Renji surges forward and kisses him, arms snaking around him to pull him in close, almost crushing Byakuya against his chest in the process. Byakuya responds without thinking about it, his eyes fluttering shut, his hands fisting in Renji’s long crimson hair.

A startled squeak leaves his lips when Renji rolls him over onto his back, pressing Byakuya down into the futon with the weight of his body, his limbs encasing Byakuya and holding him securely in place. Instinct propels him. He has their positions flipped a moment later, Renji beneath him, his hands on Renji’s shoulders and his knees straddling Renji’s lips, holding him in place, panting harshly. Renji stares up at him, pupils blown wide, the cinnamon brown of his eyes almost swallowed by the black. Something about the sight makes the fight bleed from Byakuya’s body, arousal pinging through his body.

“I overwhelmed you.” Renji says, his voice strained and hoarse. “I’m sorry, alpha.”

“You’re forgiven just this once.” Byakuya closes his eyes, another sleepy wave of arousal rolling through his body. “I’m too tired for this. I couldn’t go again if I wanted to.”

Renji’s hands slide up his thighs. Byakuya spreads his legs wider. “Lay on your side like our bodies are tied together. I’ll go slow and easy for you.”

Byakuya hums at the thought, being wrapped in Renji’s arms with Renji moving hard and hot inside of him, the slow slide, the friction— “Move over. You take up too much room.”

He would think the position more awkward than it is, but Renji makes it work, and it feels tighter this way, with Byakuya’s thighs pressed together. But Renji has been inside of him so often today, his tongue and fingers and cock, that it doesn’t hurt, just provides an interesting sensation that makes Byakuya quiver, his entire body shaking as Renji wraps his arms around him. The slow slide of Renji’s cock is better than Byakuya would have expected, the languid movements hardly disrupting the sleepy calm that’s settled over his body.

Renji kisses along his shoulder and arm, hugging Byakuya tight to his chest. “You feel so good.” he whispers, and Byakuya whimpers at him, shifts just a little closer to him. “I’ve got you.”

It might not be so bad to have him here for my heat cycles after all, Byakuya thinks.

His orgasm is slow and sweeps over him in an easy wave, his body trembling in response before he falls limp in Renji’s arms. When Renji’s knot swells inside of him, the position makes it a little tighter, makes him feel a little fuller, his body shocking in another small orgasm when Renji rolls his hips, sinking in just a little more so that his knot is nestled deep enough inside of Byakuya so as not to be uncomfortable. He hushes Byakuya softly when Byakuya whines, squirming in his embrace, the muscles in his thighs jumping.

“Was that okay?” Renji asks him, rubbing one of his thighs, fingers calming the muscles.

Byakuya’s head feels full of cotton to the very edges. It takes a concentrated effort to reply, as satisfied as he is. “Yes. I’m just… I’m so tired. Can’t keep my eyes open.”

“Go to sleep, Byakuya. I’ll hold you all night. And if you need me again, I’ll be right here to take care of you.” Renji tilts his jaw to kiss him and Byakuya leans into the kiss, into the touch and the comfort. “And in the morning, I’ll take care of you again. You can depend on me.”

Byakuya lets his head fall back down against the pillows, his arms settling on top of Renji’s own, the best he can do to hold him back in this position. It feels… Perfect, this moment, in a way he didn’t expect anything to feel given this situation. He’d walked into this expecting the worst, or moderate discomfort above all else, not to feel protected and safe and fearless in Renji’s arms.

He has time to think about Renji’s offer, but selfishly, he wants this. He wants to wake up in Renji’s arms knowing he can depend on Renji to take care of him, wants the wild and passionate afternoons, the way Renji’s rough hands found every sensitive part of his body and exploited that knowledge into Byakuya keened and almost broke into begging, desperate for more. It would be a better way to spend each cycle than jamming his body with chemicals and refusing any touch of intimacy or contact, much less something like this.

Renji’s lips on the back of his neck are the last thing Byakuya remembers before he falls asleep.