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Tank You

Summary:

Han Yoojin and Sung Hyunje go to an aquarium for the latter's birthday. Their nice day at the entirely rented out aquarium goes expected and semi-unexpected, but happy, places.

Notes:

This was originally published on Archive of Our Own for Sung Hyunje's birthday in 2025.

Guide on reading the novel and manhwa.

(See the end of the work for more notes.)

Work Text:

“You seem a bit bothered, Yoojin-ah,” Hyunje’s silky voice said in Yoojin’s ear, feeling too loud in the otherwise empty whale shark aquarium walking tunnel. The tank around them was even taller than the S-ranker, and fish – including a number of whale sharks with their gray-blue hides, white spots, and yawning mouths – swam around the coral and seaweed, heading around to swim in circles around the giant tank, even if the usual spectators were absent.

It was perhaps odd for one of the aquarium’s highlights, but given the speaker in question had rented the whole place out for the day, not that surprising.

Yoojin had thought it a horrible idea at first: what about people who’d been waiting to come see the aquarium? Lots of people arranged their vacations for such a thing! There was money and time and effort all put to waste. People’s hopes would be dashed. Not to mention it was a bit awkward wandering around the silent exhibits, just the two of them, and sitting alone in the cafeteria feeding each other overpriced but surprisingly half-decent aquarium-themed food.

“And whose fault is that?” Yoojin muttered as he clenched his hands around his upper arms and tried not to fall over. He was breathing heavily, and all the things he’d argued against for this trip were completely gone from his mind as he focused entirely on Hyunje’s left hand, which had slipped under Yoojin’s shirt while Yoojin was watching the sharks swim. Those strong and long fingers had pushed up under Yoojin’s shirt along his back, making the shorter man yelp before clapping a hand over his mouth. Then said fingers had brushed delicate patterns over the nape of his neck, seemingly uncaring the motion was lifting Yoojin’s shirt up to expose his bared back to cool air conditioning, making Yoojin shiver.

Of course, the worst was when the hand had grown bored and went down, letting Yoojin’s shirt drop, but only because that hand had pushed past the waist of Yoojin’s pants and underwear and between his tender cheeks. Two fingers slipped easily inside the shorter man, making Yoojin breathe shakily.

Hyunje pulled Yoojin closer, gazing ahead rather than at the other man, and smiling as if nothing was amiss.

Yoojin could half-see the look in the reflection on the glass.

“That toy opened you up well for me,” Hyunje teased, gently massaging Yoojin’s walls before pushing in a third finger.

Yoojin’s face burned, and he was glad Hyunje had disabled most of the cameras and told any unnecessary staff to stay out of the area. Yoojin felt a bit bad for the fish, but he supposed marine animals were easy things: they likely saw other fish screwing each other often enough, at least judging by the videos Hyuna had sent him, jokingly, about whale mating habits.

Since it was Hyunje’s birthday, Yoojin agreed to wear a toy of Hyunje’s choice on their date – so long as it could be hidden – and Hyunje had of course picked a rather large plug, which had made Yoojin squirm in the car ride over – not that Hyunje drove any faster, and he’d even seemingly taken joy in every stoplight – and nearly made Yoojin waddle as they wandered around the aquarium. They’d finally taken it out in an empty bathroom before lunch, and Yoojin felt far too open then.

He'd assumed Hyunje would fuck him there, but the man had merely cleaned him up and helped him put his clothes back on.

Somehow, that was more aggravating than wearing the toy.

Is he going to make me wait until we get home? Yoojin wondered at lunch as he frowned and ate his food, while Hyunje insisted on giving him even more. It’s not like I need him making out with me in front of the employees here, but…

It left him on edge all day, making it less easy for him to enjoy the place.

Of course I should have known he’d do something like this, Yoojin thought as Hyunje pulled Yoojin by his ass along the walkway, making Yoojin hiss and cling to Hyunje’s long coat.

When they came to a halt a short distance away, with Yoojin breathing heavily against the taller man, Hyunje tsked at him. “Yoojin-ah, your stamina is usually better than this.”

Yoojin’s face burned. It usually was, but he’d been running out of ideas to plan things for Hyunje’s birthday. The aquarium had seemed more like something they’d do for Yoojin’s birthday, but all his other ideas seemed more like family trips, while Yoojin kind of… wanted Hyunje to himself, for at least part of the big day. So he hadn’t slept well for a couple days, tossing around ideas with Hyuna until they’d landed on the final one.

And even though Hyunje had seemed pleased at the idea, that didn’t mean Yoojin didn’t stress about how to make it better, or what the kids would get up to while they were away, or how the guilds would manage, or what the press would do if they found out, or what people were saying on social media…

Yoojin was wound up with more than just Hyunje’s relentless fingers, and he tried to steady his breathing.

Hyunje reached down with his right hand to take hold of Yoojin’s chin and turn it up, so that Yoojin could stare into those burning golden eyes.

Yoojin’s lips parted in surprise at the lust he saw there. They’d been partners for a while now, and he thought he’d be used to it. But the depths of Hyunje’s devotion was still a surprise at times, like now, as the taller man leaned down for a kiss.

Yoojin shut his eyes, even as Hyunje pressed his fingers up, making Yoojin groan into Hyunje’s mouth. He was so glad they got to have this, after everything.

Yoojin almost missed the sound of Hyunje pulling something out of his pocket and tossing it on the ground, accompanied by a soft whirring that shortly faded away. When they parted, both of them breathing heavily, Yoojin couldn’t see anything.

“What did you…?” Yoojin asked with a frown, not sure what to ask exactly.

“A noise suppressant,” Hyunje said. “And it’ll keep any movement and mess inside the field, which extends slightly outward from both of us.”

Yoojin wondered who’d made such an item for him, and how he’d obtained it. But he also wasn’t sure he wanted to know. Certainly he was more interested in how this was something Hyunje had planned without telling him.

Yoojin’s face was hot as Hyunje carefully moved towards the curved glass. “You couldn’t have used that earlier?” Yoojin felt like he’d feel Hyunje’s fingers for days.

Hyunje chuckled and said, “It has a time limit. I wanted to get the most out of it.”

Yoojin wasn’t surprised by that, or by how Hyunje pressed him against the glass, letting Yoojin see the fish up close. But he wasn’t quite up against the glass: he could feel a thin layer of whatever item Hyunje had used. Which was a comfort: he was sure the aquarium staff cleaned well, but if he was going to be fucked, he didn’t want his face pressed against public aquarium glass.

Yoojin heard Hyunje unbuckle his belt. Clearly he meant business, if his fingers weren’t evidence enough.

“You never do this at your place,” Yoojin said, recalling the big fish tank in Hyunje’s main apartment. He tried not to make an annoyed sound when Hyunje’s fingers were removed, leaving Yoojin too open again.

Hyunje chuckled as he moved closer and tugged Yoojin’s pants down until they fell to his knees, baring him to the cold air. “I could if you want. You always think I’m cruel enough to those fish, though.”

“You did nearly drown me there once,” Yoojin muttered. True, it wasn’t his Hyunje, but a version of the man, still. “And you’ve lost some of those fish in the ensuing chaos.”

“Hence the item,” Hyunje said as he pressed the head of his cock through the crack of Yoojin’s cheeks. “I’d have to work hard to get through this before it wears off. The fish here will be fine.”

Yoojin clenched his hands into fists as he felt Hyunje’s cockhead press inside him far too easily. Yoojin really was too open after the plug and Hyunje’s fingers. “Have you even really been watching the fish?” He realized he was nervous. This was so public, even if he knew Hyunje had the place cleared. The animals in the tank at least were largely ignoring them.

“I’ve been reading off every species plaque we come across,” Hyunje said as he put his other hand on Yoojin’s right hip and slowly pressed his cock deeper inside Yoojin’s body. “Or did you miss the part about sea snakes? I thought you might like those.”

Yoojin admitted he’d been a tad distracted by the plug, and then wondering what Hyunje was doing, to realize Hyunje had been trying to pay attention to things. All Yoojin had thought was that Hyunje was teasing him, like usual, and pretending to care.

“I’ve talked more about clownfish mating rituals than I ever have in my life,” Hyunje said as he shoved himself inside Yoojin all the way, pressing Yoojin against the glass. “And to think, you’ve been ignoring me this whole time. I’m disheartened, Yoojin-ah.” He sounded dramatically hurt, too.

“I’ve been paying attention to you all day,” Yoojin angrily muttered. He groaned in frustration when Hyunje briefly pulled back before slamming all the way in. When Yoojin would have expected even the strongest of glass to crack, there wasn’t even the noise of a bounce. The item really was doing its job. It was like a forcefield: Hyunje could press Yoojin against the “glass”, but not break it.

That didn’t mean good things about Yoojin’s ass, though. Especially when Hyunje kept doing powerful thrusts, followed by slow withdrawals. It left Yoojin tense and aching for him to move faster. But it was also Hyunje’s birthday, and he had the right to set the pace.

A flurry of movement startled Yoojin ahead in the water: some eels and large fish Yoojin couldn’t name swam by. And a whale shark swam eerily close in a way that would have made his younger self a bit scared. He knew the glass was thick and the fish weren’t really that close, but it was a whale shark. Yoojin could fit into the thing’s mouth, easily.

“Scared, Yoojin-ah?” Hyunje asked as he pressed in all the way before placing a kiss on Yoojin’s nape. “You’ve fought dragons, gangsters, and ancient immortals. And a little fish scares you?”

“It startled me,” Yoojin said, feeling his hips press back against Hyunje’s cock. It felt embarrassing to do this in so public a place, but his right hand reached down to his own cock, pumping it desperately. He’d been antsy all day, and Hyunje was still dragging this out. “Even you get startled sometimes.” His breath felt thicker, and he was glad when Hyunje started pulling out and fucking back into him, a bit faster than before.

Hyunje made a contented noise as he licked Yoojin’s nape before moving to press his teeth against where the right side of Yoojin’s neck met his shoulders. Hyunje pressed his teeth down, not drawing blood, but making Yoojin moan at the slight flash of pain.

Yoojin’s right hand was wet already, and he was making embarrassing noises as he pressed back into Hyunje’s thrusts, and against Hyunje’s grip on his hips.

“Is this what you imagined, Yoojin-ah?” Hyunje asked against Yoojin’s skin. “When you suggested this?” Every thrust sent bursts of pleasure through Yoojin, making him gasp. After all the times they’d been together, Hyunje knew how to wring the most pleasure from Yoojin’s body, and that it kept working was so exasperating in its own way.

“I r-really wanted to s-see the fish…” Yoojin gasped around Hyunje’s cock, pressing his face to the glass, only seeing bursts of color and distant shadows through the shaking. “With you…” There were still plenty of things to worry about, but for now, they were in a relatively peaceful place in their lives, and had space for something like this. Something this ridiculous. The people they cared about were safe, and things looked hopeful.

And Yoojin was so close. He just…

“We’ll get bingsu later,” Hyunje promised, “with little jellyfish marshmallows on it,” before biting in a higher place on Yoojin’s neck.

Yoojin cried out, spilling all over himself, and grateful for the item Hyunje had used. He’d hate to leave the place dirty.

“So good for me all day,” Hyunje murmured against Yoojin’s neck, still fucking carefully into and out of him, making Yoojin grunt. “Of course I want to take my time enjoying it when it’s just us.”

Yoojin felt a little bad then, realizing he had been a bit busy with all the kids and his projects. It was rare when he and Hyunje had one on one time outside when they went to bed, usually late. They still found time, but it wasn’t the same. Hyunje had been enjoying the day for what it was, and Yoojin had only been thinking of himself…

“Did I make my husband angry?” Hyunje teased before planting a kiss on Yoojin’s right cheek.

Yoojin’s face burned in embarrassment and some other emotion he wasn’t sure he could name. “Stop saying that! Just… finish, would you? I want bingsu.” His legs were cold and he wasn’t sure how they were going to clean the mess of themselves.

Hyunje chuckled and kept going until he came, making Yoojin breathe in deeply around the filling sensation and Hyunje’s big cock pressed deep inside his body. Hyunje’s chest was pressed against Yoojin’s back, and his hands squeezed Yoojin’s hips. His breath was hot on Yoojin’s neck.

“The bingsu better have mochi on it,” Yoojin said, not wanting to fathom how he’d have to clean himself up before they could move on. Yoohyun and the rest were still watching his nutrition too much, and he wanted to snack more. But Hyunje would spoil him snack-wise on occasion, on top of the usual spoiling.

Yoojin thought bingsu was a nice way to end the day. If they could get there.

“The bingsu will have all the mochi you want,” Hyunje said before he nibbled on Yoojin’s ear. “After round 2.”

Yoojin groaned in irritation, but turned so that Hyunje could have easier access to his ear.

Notes:

Thank you so much for reading <3 <3 Kudos and comments are love! If you'd like to read more of my work, you can subscribe to the fanfic and/or my author page! My Archive of Our Own page, when it is back up, has my completed archive of work, and will be the first to be updated with new works (usually), so that is the best place to subscribe to me.

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