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“Rise and shine, Mentalist, you’re wasting the day,” Senku called as he climbed the ladder into the observatory. His nose twitched as he neared the door, a familiar flowery scent floating on the breeze, slightly sweeter than usual.
Pushing the door open, he frowned when it jammed, caught on something and leaving barely an inch wide gap. He could see a bit of navy blue fabric stuck under the door and rolled his eyes, giving the door a few experimental pushes before simply leaning his body weight onto it, the gap slowly widening until it was just large enough for him to squeeze through.
Once through, he kicked the pile of fabric away from the door, a quick sniff telling him it belonged to Chrome. It didn’t seem to have been placed in front of the door on purpose, balled into a haphazard pile as if it had been tossed aside in a hurry.
Closing the door, Senku peered into the dimly lit observatory and gave a huff of surprise. “What the hell, Mentalist…”
Gen was buried on the floor in a pile of blankets, pillows, and spare bedrolls, snugly ensconced with only a few tufts of mismatched hair poking out.
“What d’you want?” Gen grumbled from underneath his cocoon, his voice rough with fatigue and his scent thick in the air.
“Are you in heat?”
A wordless grunt was his answer, Gen burrowing deeper until even the glimpse of his hair was buried. Senku blinked when he caught sight of what looked like his winter coat tucked in amongst the nest of fabrics near Gen’s head, brow raising questioningly.
Based on his scent Gen hadn’t quite reached full heat, but the nesting behavior and lethargy meant it wasn’t far off. Most likely it had started sometime the night before, unnoticed as Chrome and Senku had camped out in the lab instead of returning to the material hut. Senku knelt on the ground near the pile and sighed, shaking his head. “Do you need me to get you anything?”
Gen’s hand wiggled out from beneath a pillow, grasping at the hem of Senku’s coat and tugging.
“This.”
Senku frowned, “My coat? What do you want that for?”
Gen grunted, tugging harder, almost knocking Senku off balance enough to topple into the nest with him. Taking hold of Gen’s wrist, Senku noted how thin and delicate it was but also just how much warmer his skin was than normal.
“You already have my winter coat, you don’t need another one.”
“Scent’s too old, want this one,” Gen whined, clearly further along in his cycle than Senku had thought, his usual filter and composure nowhere to be seen. “You‘re too busy to stay with me, gimme this.”
Senku felt a pleasant hum go through him at the idea that Gen wanted him to stay, his inner alpha preening at the notion, but pushed it down firmly. “I can’t go around without clothes on, either.”
Gen’s scent spiked at the words and Senku awkwardly rubbed the back of his neck as a blush crept up his cheeks. He’d suspected for a while that Gen’s feelings towards him were more than just friendly but it was something else to have it so clearly confirmed by the omega and, embarrassingly, he felt himself puff up a bit with pride at the idea.
“How about these? Fair enough?” He untied one of his wrist bands, holding it out over where he expected Gen’s head to be. The hand holding his jacket darted up, waving awkwardly as it tried to blindly find the scrap of fabric, disappearing under the blankets when Senku handed it to him.
The hand reappeared a moment later, making grabby motions as the sound of what could only be purring began to emanate from beneath the blankets.
Quickly removing his other wrist band, he watched Gen’s hand disappear with its prize back under the blankets, rustling around for a few moments before his head finally reemerged. His forehead was sweaty, hair mussed, and eyes barely staying open.
“I’m tired,” he grumbled, nuzzling his cheek against what Senku assumed was his pillow.
“I’ll bet,” Senku replied, remembering just how fatigued he always felt before his ruts, the body conserving as much energy as possible in preparation for the next few days. Thankfully those only happened twice a year for him whereas omegas like Gen were struck three, sometimes four times depending on their cycle.
He tried to remember the last time Gen had been out of commission and found he couldn’t quite pinpoint it. He vaguely recalled him disappearing for a few days right after the showdown with Tsukasa- but everyone had been so busy dealing with Hyoga and helping Senku pull a fridge out of his ass he couldn’t be 100% sure.
“Ryusui-chan was being annoying,” Gen pouted, eyes sliding shut again with a hum as he hugged the pillow closer. “Give him shitty jobs for the next few days for me.”
Senku resisted the urge to scowl at the thought of what the overbearingly touchy alpha had been doing or saying to annoy Gen. “Done. Anything else? You have enough water?”
Another hum, “Should. And snacks." A deep sigh, "I miss suppressants…”
Senku made a noise of agreement, reaching forward to brush the hair stuck to Gen’s forehead back. The omega gave a pleased sound, leaning into the touch.
The way heats were portrayed in the media was a grossly overblown fantasy. Sure, there was a grain of truth in how it affected an omega’s scent to be more attractive to a wider range of alphas, but only in so much as the smell wafting out of a restaurant would make someone think “oh Italian does sound good” as they walked by - a far cry from reducing alphas to mindless animals driven by lust and an uncontrollable urge to breed.
And while the cocktail of hormones that shortened refractory periods and increased libido also led to a desire for physical touch and pheromones that stoked the latent protective instincts of surrounding alphas, it didn’t leave omegas teary eyed messes begging for a knot how porn often portrayed them.
Despite that, it was common knowledge that the fastest way to alleviate a heat was to share it with an alpha, often shortening the process by several days, a fact which certainly did little to alleviate the onslaught of misinformation. Plenty of omegas took that option, enjoying a slightly more intense than usual sex marathon to flush the hormones out of their system, though plenty of others spent the days of their heat nesting and lounging around, symptoms somewhat similar to the flu - fever, chills, body aches, loss of appetite, and fatigue. Modern suppressants and birth control gave omegas more control over when and how they experienced their heats, alleviating the worst of the symptoms to the point that some omegas didn’t even need to miss work or school due to their cycles.
But in the Stone World heats were back to baseline with the only solution being several days of nesting and waiting for it to pass or sharing it with an alpha and risking pregnancy.
“Can you stay for just a little bit?” Gen asked, cheek rubbing into Senku’s palm as if trying to scent him.
Senku hesitated. He knew what he should do - set clear boundaries, avoid emotional entanglements, the logical and sound decision. But those thoughts were distant, dulled by the warmth of Gen’s face in Senku’s hand and the louder instinct within him wanting to make the other man feel better.
His fingers stroked up through Gen’s hair again as he settled cross legged beside the nest, “For a little bit. I left Chrome in the lab and you know how he gets when he's unsupervised.”
Gen’s nose wrinkled up in a grimace, “Ugh… take his stuff when you leave, it stinks.”
Senku peered back at the pile of fabric by the door in understanding, “Ah. And mine doesn’t?”
Eye cracking open just enough to give him a withering look, Gen huffed. “Yours smell like you .” He nuzzled more firmly into Senku's hand, eyes slipping shut again. “Should only smell like you and me in here.”
Senku felt a tug at his chest at the words, languid, possessive, and honest . The mentalist was truly feeling it for him to be this unfiltered, this cavalier and unguarded with his requests. He knew there was no way Gen would have asked him to stay normally without hiding it behind layers of double speak or at least a thin veil of jocularity to lean on should he refuse, but here in the quiet warmth of the observatory his desire for comfort was stronger than his desire to hide.
It was true that the observatory had unofficially become their space, the novelty of the telescope wearing off from the villagers rather quickly as other more impressive devices were created. The visitor count dwindled even further as their scents permeated the room, heavier even than how Senku’s scent clung to the lab. It made sense that the omega found comfort in familiar surroundings and wanted to limit anything his instincts identified as not belonging.
The fact that he’d identified Senku as belonging sent a pleasant thrum of warmth through him.
Minutes passed in silence, the heavy scent in the air paired with the quiet rise and fall of Gen’s breathing grounding and oddly soothing. Senku exhaled slowly, adjusting his posture as he took a glance around the observatory again, taking note of all the things Gen must’ve moved or rearranged as he built his nest. Things were out of place, shoved against the walls or piled atop each other haphazardly, a different sort of chaos than usual but it was somehow comforting to think of it as Gen’s chaos.
Gen, whose body was clearly working overtime, caught in the beginning stages of its cycle, a sheen of sweat on his temple and a flush climbing his cheeks. Senku could feel the pull of it, not the way the media implied alphas would - some uncontrollable beast inside him fueled by testosterone and unrestrained libido - but a quiet, steady tug in his chest.
The part of him that wanted to help and protect. That hated seeing Gen vulnerable and uncomfortable and looked for anything he could do to make it easier.
He didn’t feel like that when other omegas were in heat. Usually it was a simple empathetic “that sucks” sort of feeling, making sure they had the bare necessities and leaving them to it. But with Gen he found himself starting to create a list of additional materials to have around or possible remedies to ease the symptoms for next time.
“Hey,” Gen said suddenly, voice low and sleepy, eyes half lidded as he looked up at him, head nudging against Senku’s hand making the scientist realized he had stopped stroking the other man's hair at some point. “I can hear you thinking. You don’t have to do anything, just being here helps.”
“We’ll see if you still feel that way in a few days,” Senku replied dryly, trying to mask the sudden tightness in his chest.
“I will,” he murmured, following Senku’s hand when he nearly pulled it away, silently protesting the loss of contact and eyes drifting shut again. “You’re a good alpha.”
And then he was asleep, breath slowing and tension melting from his limbs. Senku stayed still for a moment, unsure if he should feel proud or terrified at Gen’s praise. He was used to Gen’s usual flattery, but this had been different - no calculation or sly manipulation. Just bone-deep exhaustion and an unguarded sincerity that Senku wasn’t prepared to handle.
“Idiot,” he muttered, brushing his hand over Gen's hairline again, taking a moment to estimate his temperature. “You shouldn’t say stuff like that, someone might take you seriously.”
Still, his hand lingered.
He waited several more minutes, rooted in place by the weight of Gen’s trust curled beside him, finally pushing himself to his feet. He avoided the parts of the floor he knew creaked, picking up the pile of discarded fabric Gen had banished by the door.
Only smell like you and me in here .
Ridiculous.
He pulled the door open, mindful of the beam of light crossing into the dimly lit observatory, shielding it from passing over Gen’s face with his body as he started to slip out.
“...Don’t forget to come back.”
He froze at the softly mumbled words, drowsy and possibly even unconscious, hitting like a hammer to his chest as Gen curled tighter under the pile of blankets.
Senku didn’t look back. He didn’t have to.
“I won’t,” he said, and shut the door behind him.