Preface

Birthday Hot Spring Trip
Posted originally on the fanfiction.lol at https://fanfiction.lol/works/1576.

Rating:
Explicit
Archive Warning:
No Archive Warnings Apply
Category:
Slash (M/M)
Fandom:
My S-Class Hunters | The S-Classes That I Raised
Relationship:
Han Yoojin/Sung Hyunje
Characters:
Han Yoojin, Sung Hyunje
Additional Tags:
POV Han Yoojin, Top Sung Hyunje, Bottom Han Yoojin, Hot Springs & Onsen, Anxiety, Angst with a Happy Ending, Post-Canon, Established Relationship(s), Boys Kissing, Anal Sex, Bath Sex, Plot What Plot/Porn Without Plot, Birthday Sex
Language:
English
Stats:
Published: 2026-02-08 Words: 1,880 Chapters: 1/1

Birthday Hot Spring Trip

Summary

Han Yoojin’s loved ones take him to a hot spring for his birthday, and Sung Hyunje gets the pair of them a guest house alone together. But Han Yoojin is haunted by birthdays past. Thankfully, his partner is there to make things better!

Notes

This was originally published on Archive of Our Own, to celebrate Han Yoojin's birthday in 2026!

A guide for reading the novel and the manhwa

Birthday Hot Spring Trip

“Yes, I promise I’m fine! Love you, see you soon!” Han Yoojin finally hung up the call with his brother and lowered the phone from his ear as he stood in the mostly empty fancy guest house in Youonejae. His suitcase was sitting in the bedroom, mostly still packed, since he’d gotten here and was still unsure he should stay.

Where he was standing, he could see through the glass entryway doors to an idyllic lawn and a set of outdoor seating they likely wouldn’t end up using in the cold. But it looked pretty, anyway.

“It’s your birthday, hyung,” Han Yoohyun had reminded him time and again, though he hadn’t liked leaving Han Yoojin alone in such a public place, even though Han Yoohyun was going to be staying at another room in the resort.

“The young master is still worried about you?” Sung Hyunje asked as he walked out of the kitchen area holding two hot cups of tea, one of which he handed to Han Yoojin. The S-ranker wore a loose white shirt and relatively casual pale brown pants. His silver-blonde hair was still finely brushed back, and his golden eyes were bright in the afternoon sunshine.

Han Yoojin took the cup and warmed his hands. The place had good climate control, but it was still February and cold. “He’s… well…” After all the years before the regression of celebrating his birthday alone or avoiding celebrating it at all, it was odd to say that Han Yoohyun was being too much. Han Yoojin was happy his little brother was focused on him.

“We’re going to have a big dinner tonight with everyone,” Sung Hyunje said as he moved closer to Han Yoojin, crowding him a bit. “It’s not like you’ll be apart for long.” Sung Hyunje reached out to rest his left hand on Han Yoojin’s hip.

Han Yoojin breathed in deeply and then drank his tea.

“Let’s go out for a dip before then, hmm?” Sung Hyunje said before he leaned forward to press a gentle kiss to Han Yoojin’s forehead. “I think it’ll warm you up well.”

Han Yoojin nodded, and then followed Sung Hyunje back to the bedroom to get changed. They were at the hot springs to be in the hot springs, after all. And he wasn’t going to waste it.


“Isn’t it cheating to use dungeon items to warm the air?” Han Yoojin asked as he settled in the water wearing just a swimsuit. Normally, he’d have worn more because of the frigid February temperature, but Sung Hyunje had employed some items around the area to keep the air around their outdoor tub warm. Soaking in the hot water was still nice after traveling here and being in the cold for so long, but it wasn’t quite the same as when it had been freezing.

“I can turn it off if Yoojin-ah wishes,” Sung Hyunje said as he walked over in black swimming trunks to join his partner in the water. Of course he was showing off his muscular chest and good-looking limbs, making Han Yoojin think about his own body and the dietary regimen Han Yoohyun had him on.

“No, it’s fine,” Han Yoojin said, not wanting to miss out on things. And it meant it was easier being in the water. There were no birds and there was enough separation that they couldn’t hear anyone else around: Sung Hyunje had booked the area so it was just their group at the resort, in part for safety. He’d also arranged things so the rest of their group were in rooms farther away. Han Yoohyun had objected, given the danger they all knew Han Yoojin could be in at times, but Sung Hyunje had asked what he thought Han Yoojin would be in danger of when Sung Hyunje would be beside him at all times.

At which point, Han Yoohyun and Sung Hyunje had almost started fighting, but Han Yoojin had broken them up to get them to stop.

Sung Hyunje sat down in the shallow water next to Han Yoojin and pulled him close, so that Han Yoojin leaned back against Sung Hyunje rather than the black tub sides. Then Sung Hyunje left his hand resting on Han Yoojin’s left thigh.

Han Yoojin shut his eyes and leaned back against Sung Hyunje’s chest, trying to let go of all his usual worries and concerns. This hadn’t exactly been his idea, absent a comment he’d made while watching TV one day: “Hot springs seem nice.” Han Yoohyun and Sung Hyunje had of course gotten wind of this from Park Yerim, and this entire trip had been planned for Han Yoojin’s birthday.

Han Yoojin felt a bit mixed about the fuss. He should be happy, shouldn’t he, that so many people cared about him? But he kept remembering years past…

“Yoojin-ah is quiet today,” Sung Hyunje said in the silence. “More than usual. Normally you’d be fretting over the young master’s whereabouts, or what most anyone else is up to. Do you miss Peace so much?”

Han Yoojin snorted and said, “No, I just…” He looked down and rested his hand on Sung Hyunje’s left thigh, reminding himself this was all real and not a fantasy. “It’s strange to have another year where I’m surrounded by people.”

Sung Hyunje lightly moved his thumb back and forth on Han Yoojin’s leg. “Things were hard, before you went back in time.” They both knew now, embarrassing as it was for Han Yoojin.

“Yes,” Han Yoojin said, quietly. “I just… Back then, I only wanted to be around Yoohyun-ie. And I still want that. But it’s weird to not have that odd hurt inside me and still remember it. Like… echoes, almost.” It felt odd to say this aloud, but he’d voiced worse to Sung Hyunje. The man had seen the worst of him and stayed with by Han Yoojin’s side regardless.

Sung Hyunje settled a little more and said, “I’ve seen your brotherly bond up close and can’t say I fully relate to it.”

Han Yoojin knew that.

“But,” Sung Hyunje said, “I think of when Park Hayul kidnapped you, and I couldn’t do anything. And, of course, we managed eventually. But… while my life has been difficult, I suppose I can understand something of what it’s like to have someone you love ripped from you.”

Han Yoojin’s face heated. “That…”

“Though it’s not a sibling,” Sung Hyunje said with a chuckle. “I can’t say I feel about Sigma the way you do about the young master.”

“Certainly not,” Han Yoojin said. And it wasn’t like Sigma was Sung Hyunje’s brother, even if they pretended at it.

“You still struggle to acclimate,” Sung Hyunje commented. “It’s part of why you so desperately look after everyone.”

Han Yoojin’s lips twitched. “Well…”

“Which means I need to be working harder to make you better enjoy your birthday,” Sung Hyunje said. Then he pulled Han Yoojin closer and kissed his head just over his right ear.

Han Yoojin smirked and said, “It’s not really your job to do that.”

“Yes it is,” Sung Hyunje said primly as he settled Han Yoojin more firmly between his large legs. “It was an agreement I made with your brother to allow me to have a room of my own with you for the night.”

Han Yoojin wondered just how much his brother and Sung Hyunje had chatted about when Han Yoojin wasn’t around.

Sung Hyunje wrapped his arms around Han Yoojin’s midsection, pulling him closer. “You’re still distracted, Yoojin-ah. But I know something that might keep you in the moment.” Pointedly, the extra closeness meant that Han Yoojin could feel the S-ranker’s thick cock in his swimming trunks.

“I suppose that’d work,” Han Yoojin said. At least it’d keep him focused until dinner time. “But are you sure they’re okay with people fucking in the hot spring rather than the bed?”

“I paid them a lot to clean the place before and afterward,” Sung Hyunje said as he reached down to push his fingers under Han Yoojin’s waistband. Water found its way inside Han Yoojin’s shorts, and he breathed in deeply at the heat, even as he adjusted.

“I can’t stay in here forever, you know,” Han Yoojin noted. His body was a lot stronger than it used to be, but there were limits.

“I’ll go quickly,” Sung Hyunje said as he pressed two fingers inside Han Yoojin’s entrance, making Han Yoojin squirm even more while pressing his upper back against Sung Hyunje’s chest.

“I’m fine,” Han Yoojin said, trying to keep his feet still as Sung Hyunje’s fingers squelched inside him with all the water. “You can just go.”

Sung Hyunje kissed Han Yoojin’s right shoulder, and then moved his lips along the bare skin there and up to Han Yoojin’s neck, sucking lightly before pulling away.

Han Yoojin’s breathing picked up, and he tightened his grip on Sung Hyunje’s right arm.

Sung Hyunje removed his fingers at last, and then reached down to lip Han Yoojin slightly, before messing with his own swimsuit. When he lowered Han Yoojin back down, the F-ranker could feel Sung Hyunje’s bared cock pressing against him. Sung Hyunje carefully maneuvered Han Yoojin over it, and then pressed easily inside of him, pulling Han Yoojin all the way back to Sung Hyunje’s chest.

Han Yoojin gasped at the fullness. The S-ranker was irritatingly large, even if it meant it kept all of Han Yoojin’s attention.

Sung Hyunje’s right hand moved up to Han Yoojin’s chest, where he latched onto Han Yoojin’s right nipple and tweaked it in his fingers. The steam from the tub made everything slick.

Han Yoojin panted and slid back even more on Sung Hyunje’s cock, which wasn’t even moving, and wondered why he already felt a little tired. He needed to stay awake for the dinner later.

“It does depress me a bit,” Sung Hyunje said as he began moving his hips and making the water splash a bit around them. “That I’m insufficient for my dear partner.”

Han Yoojin groaned and reached for his stomach, feeling where Sung Hyunje was pressing deep inside him. “As if I could ignore you.”

Sung Hyunje chuckled and reached forward to bite Han Yoojin’s ear.

Han Yoojin groaned and reached for his own cock, taking  hold of it and stroking it as they splashed in the water. As the heat and sensation overcame him, making him feel wrapped up in warmth.

Not alone and cold and sad, drinking to forget.

Sung Hyunje’s hands grasped him tightly.

Han Yoojin yelped as he came, spilling in the water.

Sung Hyunje needed a few more thrusts before he emptied himself inside Han Yoojin’s body.

Han Yoojin felt the mess leaking out of him a little, making the water even filthier. He wondered, vaguely, if it was just something the filters dealt with. He doubted it.

“Happy Birthday, Yoojin-ah,” Sung Hyunje said right in Han Yoojin’s right ear.

Han Yoojin turned to face the S-ranker, who gazed at him hungrily. Han Yoojin reached back and pulled the man’s face close for a kiss.

Sung Hyunje reached out and pressed his hand over Han Yoojin’s belly, right where his cock was pressed, making Han Yoojin groan into his mouth.

Afterword

End Notes

I find it deeply hilarious the set-up for this basically ended up happening in the manhwa. Goes to show: be the change you want to see in the world.

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.

Rebloggable on tumblr * Retweetable on twitter * Blue Sky Social

My other S-Class fanfics

Please drop by the Archive and comment to let the creator know if you enjoyed their work!