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When Gen and Senku finally got their heads out of their asses and admitted they liked each other, the Kingdom of Science gave a collective sigh of relief and a cheer. No more pining, no more longing looks and awkward tension, no more will-they-won’t-they dramatics.
Finally some peace.
Or so they thought.
1.
Gen wandered by the clearing in front of the lab, catching sight of Senku puttering around inside with a fond smile. He briefly considered going in to observe and make a nuisance of himself, but figured they could still stand to have some personal time away from one another despite their new relationship status.
Instead he ambled over to where Chrome was crouched over a large vat of steaming liquid, peering into it curiously. “Doing anything interesting, master explorer?”
The Stone Age man grinned wide, “Just a totally bad new dye formula for clothes, it makes a really nice purple color.”
“Does it?” Gen asked, interest piqued at the mention of his favorite color.
“For some reason the dye never worked before and would just wash out, but Senku told me if I used some alum on the fabric first it should stay brighter. See?”
Gen leaned closer as Chrome pulled the fabric out, his fingers stained in shades of red and seemingly unbothered by the steaming temperature of the water as the rich plum fabric dripped back into the pot.
“Oh, very ice-nay! Will it stay this dark when it dries?” He was reaching out to prod at the dripping fabric when a familiar hand wrapped around his wrist, calloused and warm.
“Oi, Mentalist, you’re needed. Now.”
Senku’s voice was deceptively flat, standing close enough that Gen could feel the warmth of him through his coat.
Chrome frowned, “For what? You sent me out here because you didn’t need any help.”
“For… something.” Senku replied, clearly not having thought that far ahead. He didn’t wait for either to respond, pulling Gen behind him as he retreated.
“Senku-chan, what on earth…”
They ended up in the lab and Gen waited for instructions or materials, confusion settling in as nothing followed and Senku started prodding whatever he’d been working on before.
“So did you… actually need me for anything?”
Senku paused and Gen could see his gaze avert, tips of his ears turning red. “Can’t I just want you here?”
Heart melting, Gen draped himself over Senku’s back, arms wrapping around his shoulders as he nuzzled into his hair. “Of course you can, dearest, but there’s no reason to act so silly and ecretive-say about it, you can just ask. What, were you afraid Chrome-chan was going to tease you?”
Senku rolled his eyes and muttered something under his breath, shifting slightly to better accommodate Gen’s weight so he could work and Gen hid a smile in his hair, idly rubbing his thumbs over the front of Senku’s shoulders.
He certainly hadn’t expected Senku to be the clingy type but he wasn’t about to complain if it meant he had more opportunities to cuddle with his new boyfriend.
2.
Gen hummed to himself as he shuffled through his playing cards. He had finished the task Senku had asked of him that morning and found the scientist too busy with whatever contraption he was working on with Kaseki to assign him anything new. He took the opportunity to do nothing and not be chastised for it without question, doing a quick circuit around the Roppongi base in search of any conflict before finding a quiet place to sit and relax near the treeline.
“Ukyo-chan, catch anything good?” he called as the archer walked by, the contraption Kaseki had built to hold small game laden with fresh kills.
Ukyo grinned, gesturing to the haul as he drew closer, “A few rabbits and a pheasant, nothing too crazy,”
“If it means no fish for a few meals I am fine with whatever you atch-cay,” Gen avoided looking at the animals too closely, “even the really cute ones.”
“Mm, definitely the hardest part, for sure. It sounds terrible but it’s a lot easier for me to shoot down a bird or a deer than a rabbit. But when survival’s on the line beggars can’t be choosers.”
Gen tilted his head sympathetically, “Helps that Francois-chan can turn them into such delicious meals, though, doesn’t it?”
“Even as a hardcore vegetarian, I have to admit they have a way to make meat somewhat appealing,” Ukyo laughed. “Can’t wait to see what they can do with better ingred…ients…?”
Ukyo trailed off, watching as Senku sidled up next to Gen and looped an arm around his waist to pull him against his side. Gen blinked up at him, seemingly more confused by his sudden appearance than his clinginess, but still didn’t argue or try to wriggle away.
“Sorry, need to borrow him.”
Missing the way Ukyo looked between them with bemused understanding, Gen tilted his head. “You just said you didn’t need me for anything,”
Shrugging, Senku rubbed his hand over Gen’s hip, “No, I said I was too busy to think of anything I needed you for. I’m not busy anymore and I need you for something.”
Raising his eyebrow skeptically, Gen pursed his lips, “And what is that omething-say?”
Senku shoved his pinky in his ear distractedly, not bothering to look at him, “Why don’t you come with me and find out?”
“Why don’t you tell me so I can decide if I need to make up an excuse to get out of it?”
“Well now I’m definitely not telling you,” Senku snorted with a roll of his eyes, starting to tug Gen by his hip in the direction of the lab.
Ukyo watched with a barely hidden smirk as Gen obediently followed, complaining the whole time but doing nothing to escape. He sometimes forgot that Senku was still a teenager until the small flashes of immaturity popped up - at least this one was tolerable for now, and honestly a little cute.
And he was sure Gen would put a stop to it if it got too bad.
3.
“Gen!”
Taiju’s booming shout was the only warning Gen had before he was lifted bodily off the ground in a bone crushing hug.
“Oof! Nice to see you, too, Taiju-chan,”
“I’m so glad you and Senku finally got together! Me and Yuzuriha were afraid he’d never find anyone he liked!”
Gen laughed, “So you’ve said. Many times over the last three months, in fact.”
“We’re just so happy!” Taiju rocked from side to side, swinging Gen along with him and the mentalist rolled his eyes as he silently counted down until Taiju would finally release him. The other man’s bear hugs usually lasted around a minute or so until he’d exhausted his desire to show his affection physically. The best course of action was to just wait it out - trying to wriggle free or talk your way out of it often led to Taiju getting distracted and forgetting he was holding you captive to begin with.
This time, however, it seemed he wouldn’t have to wait as a familiar voice suddenly piped up.
“Put him down.”
Taiju made a confused sound at the flat, unamused tone of Senku’s voice, turning to find the scientist staring him down. “Oh hey, Senku! I was just telling Gen how-“
“Down.” Senku repeated, expression sharp as if he was attempting to calculate the force needed to break Taiju’s arms if necessary.
Blinking for a moment, Taiju broke into a wide grin and gave a loud, booming laugh, gently setting Gen down as if he were handling a baby bird. Feet having barely hit the ground, Gen found himself pulled into Senku’s (much gentler but still firm) embrace.
“Ah, hello, darling, did you need something from Taiju-chan?”
Grunting the negative, Senku dropped his chin to Gen’s shoulder, nudging his temple against Gen’s until the mentalist raised his arms to hug him back.
“Did you just want a cuddle?” He chirred, eyebrows raised in amusement as Senku rubbed his head against him more firmly. Snickering, Gen rubbed his hands up and down the other man’s back, wiggling happily at the huff it earned him, annoyed but not moving away.
“It’s great to see Senku so happy,” Taiju beamed, face split by a wide, toothy grin. “I’m glad it was you, Gen!”
The mentalist blushed but craned his head back to give him a small smile, “Yes, well… what can I say? I have a way with stray animals,”
“Hey!”
“Shh, my feral little raccoon,” Gen cooed sarcastically, patting Senku’s head in an overly playful motion reminiscent of a toddler petting a cat for the first time. “Just let me love you,”
“You’re the worst,” Senku grumbled, though despite his tone his hands clutched at Gen tighter. “Don’t even know why I put up with you,”
Gen smiled, kissing his cheek with a loud, wet smack, “Funny, sometimes I think the same thing about you,” he teased, shifting to rub their noses together annoyingly. “But then I remember how cute you are.”
Taiju laughed at Senku’s resulting grumble, head tilting at the sour look the scientist sent him from over Gen’s shoulder. A look of understanding crossed his face and he gave a decisive nod and a thumbs up before starting to walk away. “He’s all yours, buddy!”
Not catching the true meaning behind Taiju's words, Gen craned his head back and whined, “Oh, don’t tell him that, Taiju-chan, he’ll come up with some silly project for me to do! Come back and pretend we were working on something and save me!”
Snorting, Senku pulled him closer, watching as Taiju walked away. “Too late, you’re coming with me.”
4.
Despite Gen taking every opportunity to cuddle with or hold Senku’s hand regardless of who was around them, he did have some limits when it came to broadcasting the more intimate parts of their relationship to the rest of the world.
“Hey, Gen, were you sparring with someone?”
Gen blinked in surprise, looking down at Suika with his brow knit in confusion. “No? Why would you think that?”
Tilting her head, Suika pointed at his neck, right below his ear, “You’ve got a bruise.”
Senku glanced up as Gen slapped his palm over the offending mark peeking out his collar and smirked. “That’s my fault.”
“Senku-chan,” Gen warned, voice low as Senku snickered.
“What? I didn’t hear you complaining when I was doing it,”
“Ut-shay up, or you’re never doing it again.”
Suika looked even more confused, “You were sparring with Senku?”
“Oh they were doing something, but it’s not usually called sparring,” Kohaku teased as Gen’s face started to flush.
“Kohaku-chan…” Gen growled through clenched teeth, which only made Kohaku laugh harder.
Do you have any other bruises?” Suika looked up at him in concern, eyes widening with realization. “Should I go get Bibi?”
“No, Suika-chan, that won’t be ecessary-nay.”
Senku’s smirk had gradually become smugger, sidling up next to the mentalist and resting a hand on his shoulder, thumb rubbing up and down his neck where plenty of other bruises were hidden by his high collar. “Don’t worry, Suika, he’s fine. He just bruises more easily than other people.”
Kohaku snorted, rolling her eyes, “Yeah, I’ll just bet he does,”
Suika gasped, tugging on Kohaku’s dress in a panic, “Isn’t that like when Argo only ate vegetables all winter and his legs got all bruised up? He got really sick!”
“Don’t you worry, Suika-chan,” Gen’s voice was light but both Kohaku and Senku could hear the thread of irritation running through the words, “it has nothing to do with my diet or being sick. We just got a little… carried away, is all.”
Kohaku dodged the swipe Gen took at her, practically cackling at just how pleased with himself Senku looked.
Suika didn’t seem convinced, “Really? You’re okay?”
“He’s fine, Suika, don’t worry,” Senku pressed a little harder where he knew one of the marks sat, enjoying the way Gen shivered against him, “I’ll make sure to be less rough with him next time.”
Gen could tell by his tone that he’d be doing the exact opposite and pinched his side in retaliation. They’d be having a chat a little later when little ears weren’t around.
5.
Gen sighed internally, shifting his weight slightly from one foot to the other. What Senku had assured would be a “brief meeting” had quickly become a long, drawn out discussion that he knew would not be ending any time soon. Especially when Senku pulled out the drafting paper and started sketching.
He glanced around the room, taking note that all of the available chairs were in use (or missing, for what reason who knew). He could sit on the floor, he supposed, waiting for his input to be needed, but with everyone else sat at the table that felt a bit childish.
“Oh, Gen, you can have my seat,” Ukyo moved to stand, pausing halfway through when Senku took hold of the mentalist and pulled him onto his lap. “Or not.”
Gen gave a little yip of surprise, immediately trying to climb his way off, “Senku-chan, what are you-“
Senku didn’t respond, just shifted Gen so his legs were draped over his lap and looped his free arm around his waist to hold him still as he continued sketching. “If we move this wall over, it’ll open up more space for-“
“Senku-chan!”
“Is he really going to just pretend this isn’t happening?” Chrome asked, shaking his head at the sight before them.
“You know, in hindsight we should’ve seen this coming,” Ukyo grinned. “It’s actually kind of cute.”
Ryusui laughed, “True, I mean he writes his name on damn near everything, that should’ve been our first clue.”
“If you’re not going to focus on this we can meet again tomorrow,” Senku said coolly, gesturing at the schematic on the table as if pulling Gen into his lap in front of all of their friends was a perfectly normal thing to do.
Gen huffed, “If you could all give us the room, I believe I need to have a discussion about boundaries with this one,”
“Surprised he hasn’t bitten your head off at this rate,” Chrome joked to Ryusui as he got to his feet, following the other two towards the door.
Ryusui cackled, “Oh, trust me he didn’t have to. I learned a long time ago how to handle jealous partners and could tell right away that I should keep my distance...”
Voices faded as the door shut and Gen turned his attention back to Senku. “And now we’re going to talk about why you’ve been acting so weird.”
“I’m not acting weird.”
Gen raised a brow and pointedly looked at the arm around his waist and his position perched with his legs resting across Senku’s lap. “Uh huh.”
Senku stayed silent for several moments before letting out a sharp exhale. “Fine. I’m… jealous.”
“That I gathered, what I can’t seem to figure out is why. I'd like to think I haven't done anything to bring on this sudden change?”
“It’s not a change,” Senku grumbled, ears flushing red as he avoided Gen’s gaze. “I’ve always been… annoyed when you talk to other people. Or paid attention to them. But before we were… together it was pointless. There was no logical reason for it because I had no claim over you so I just sort of… ignored it best I could.”
Gen felt Senku shift underneath him, the arm around his waist curling tighter, Senku’s face tucking itself into the curve between his neck and shoulder warmly.
“But now you’re mine and I can tell everyone else to fuck off. I can keep you close and make it clear to everyone else to back off,”
Gen laughed, a delighted shiver running down his spine at Senku's breath warm on his skin. “Oh? So you’ve started acting like a caveman because now you can?”
“No, I’m acting like a caveman because I’ve wanted to for a long time and now I’m allowed to.” He paused for a moment, pulling back far enough to look up at Gen. “Right? You don’t mind?”
“Mind?” Gen purred, practically glowing. “Dearest, feel free to manhandle me enever-whay you want to.”
Making a sound of acknowledgement, Senku maneuvered his hold to lift Gen up, turning him so the mentalist was fully straddling him, hands settling low on his hips to hold him in place. As Gen’s weight settled, he latched his mouth onto the space just behind the hinge of his jaw and began to suck.
“Oh,” Gen breathed, able to feel heat rise to his cheeks as well as settle low in his stomach. “Right now works,”
Senku pulled back with a smirk, the circle of reddish purple stark even against the flush of Gen’s skin. “Good.”
+1
Gen had known straight away just how amazing Senku was. How magnetic. People were drawn to him, and it wasn’t difficult for their admiration to transform into warmer feelings. Gen himself had gone through it, he’d just been lucky enough that Senku felt the same about him.
Others were usually fended off by a caustic barb or Senku’s obliviousness to their attention. For as attentive as Senku was with Gen, he was blissfully unaware or otherwise dismissive of romantic intention from any other source - almost as if he’d installed some sort of firewall that bounced it all away to only let Gen through.
And because of that Gen didn’t get jealous. He was very aware of how much Senku loved and wanted him and was exceptionally secure in their relationship.
That didn’t mean he didn’t get annoyed though.
“Oh, wow, Senku! You’re so smart, I never would’ve thought of that!” Luna simpered, eyes big and chest thrust forward as she twirled a lock of hair around her finger.
Senku grunted, not even looking up from what he was doing.
It was sad almost, how hard the girl had been trying. Gen had heard from the others about how she had latched onto Senku while Gen was back at Xeno’s base, how she had seemingly misunderstood or just ignored every brush off the scientist gave her. It seemed that her attempts at getting his attention were growing more frequent and more blatant as time went on.
And as annoyed as Gen was, he knew better than to start a pissing contest when they needed her medical expertise. She was a valuable new member of their team and it would do them no good to introduce animosity - so it was best if Gen just let it sort itself out. Senku wasn’t subtle, she’d get the message eventually.
“If you want, we could go to the medical bay and I could check your bandages for you?”
Her tone was a ridiculous attempt at being seductive, elbows pressed in to try and enhance her cleavage, and eyelashes fluttering. Rolling his eyes, Gen was about to walk away when Luna reached forward and rested her hand on Senku's shoulder.
Before he realized it, he had marched across the deck, curling his fingers around Senku’s jaw to lift him into a demanding kiss. With obvious tongue.
Senku didn’t falter, simply kissing back, hand finding Gen’s waist to pull him closer.
When Gen pulled back for air, he leveled a saccharinely sweet but dangerous smile at Luna. “Sorry, Luna-chan, I need Senku-chan quite urgently now.”
Flushing clear to her hairline and mouth working uselessly, Luna could do nothing but squeak and dart away, steam practically pouring off her in her embarrassment.
Senku laughed, pressing a wet, open mouthed kiss to the hinge of Gen’s jaw where his most recent mark had started to fade, smirking at the shiver it always earned him. “Is someone jealous?”
His voice was smug yet pleased and Gen hummed.
“So what if I am?”
“You’re usually a lot more subtle about it… not that I’m complaining about the results." Another sucking kiss with a delicate scrape of teeth, "Or the methodology.”
Gen practically purred, letting Senku pull him into another kiss, looping his arms around his neck to hold him close.
“Yes, well…”
He rubbed his nose against Senku’s sweetly and gave a devious nip to his lower lip.
“I learned from the best.”