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• ───────────── •
The math lab kept strange hours and stranger moods. At four in the afternoon it was fluorescent, stale, and empty - except for Min Yoongi, who was babysitting a stack of Calc II quizzes like a dragon hoarding mediocre treasure.
He tapped a pen against a margin note. “Limit does not mean ‘vibes,’” he muttered, then crossed out a sprawling answer that simply read “yes.” “Someone even drew a heart next to ∞. I admire the optimism.” It was a statistical impossibility that anyone had passed the quiz on purpose.
The door banged open.
A gust of late sun, cologne and coconut-something rolled in with Park Jimin, who wore an SNU volleyball warm-up jacket unzipped over a practiced grin and a pair of shorts that had a personal vendetta against gravity. He held a half-eaten energy bar in one hand, a water bottle under his arm, and the exact expression of a golden retriever who just remembered math exists. He radiated confidence like a poorly contained exponential function.
“Hi!” he chirped, scanning the room. “Is this the math place?”
Yoongi blinked at him. “This isn’t the gym.”
Jimin’s grin widened. “Coach said I need to fix my math or I’ll be bench décor. Do you... fix math?”
“I break it, mostly,” Yoongi said.
“Seriously though. Do you know math? You look like you know math. Can you help me?”
“Yes,” gesturing at a chair. “Sit. We’ll minimize your suffering subject to existing constraints. What do you need help with?”
Jimin flopped into the chair with the boneless grace of an athlete and slid a worksheet forward. “So we’re doing... slopes. Like angles. Slop?”
“Slope. It’s slope.” Yoongi took the sheet and glanced up, not on purpose, but his gaze snagged anyway. Jimin’s face had the kind of proportion that made painters ruin their wrists. Cheekbones and mouth aligned in a neat 1:1.6 that wandered dangerously close to the golden ratio, and the symmetry felt like a personal attack.
Annoying. Also statistically unfair.
“I’m Park Jimin,”
“I know, everyone knows. I’m Yoongi, Professor Han’s teaching assistant.”
Jimin beams at him, and Yoongi feels like his heart is non-existent. The sine of that smile is too steep for his comfort.
“So, what’s a derivative again?” Jimin asked, hovering a pencil over a clean page. “Is that like... an energy drink?”
“Congratulations,” Yoongi said. “You’ve broken math.”
Jimin laughed, bright enough to bounce off whiteboards. “You’re kinda funny for a nerd”
They spent forty minutes arguing with a parabola. Jimin kept drawing little volleyballs next to his answers, and Yoongi kept rephrasing terms until they stopped sounding like snacks. By the end, Jimin could identify slope, if under duress, and Yoongi had learned three things: Park Jimin listened seriously, smiled too big, and smelled faintly like sunscreen and summer.
On his way out, Jimin wiggled the pen he’d used. “Can I—?”
“No,” Yoongi said, snatching it back, because sharing pens is how you get attached. The door closed on Jimin’s laugh, and it was only after silence returned that Yoongi realized he’d been holding the marker too tightly, like it meant something it didn’t.
• ───────────── •
A week later, the math lab was quieter; the fluorescent lights blinked like they were trying to learn Morse code. Yoongi was halfway through an office-hours crossword he didn’t remember starting when Jimin swooped in wearing shorts. Not just shorts - the shorts. The ones that treated his quad muscles like an art exhibit.
Yoongi looked down at his crossword. 17-Across: “Object of obsession.” The clue felt personal. Statistically, correlation does not imply causation, but his eyes keep proving him otherwise.
“Ready to repair my relationship with slopes?” Jimin asked, bracing his elbows on the table. His knees bumped the underside. He leaned forward. Shorts followed.
Yoongi lost his train of thought. “Your thighs,” he heard himself say, “have the proportions of a Greek statue.”
Jimin blinked, slow as a cat. Then: “So you’ve... studied them?”
Yoongi wanted to walk into the sea. “In a purely mathematical sense. Ratios. I’m commenting on ratios.”
“Oh,” Jimin said, very solemn, then leaned closer, conspiratorial. “Like... the ratio of these shorts to your lifespan?”
“Approaching zero,” Yoongi muttered. “Function diverging to negative infinity.”
They worked, if that was the word. Jimin tapped his pencil against his notebook, listening with eyebrows knit, tongue peeking out at the corner of his mouth like it was trying to cheat off his own notes. Whenever he understood something, he brightened - smile full wattage - as if his brain enjoyed fireworks. And whenever Yoongi forgot himself, he returned to the safe territory of sarcasm and instruction—
“Stop smiling like that. My linear regression just broke.”
—which, annoyingly, Jimin found hilarious.
They were sketching a parabola when Jimin said, “You should come to one of our games.”
“For what purpose,” Yoongi said flatly, “aside from public suffering.”
Jimin’s mouth tipped sly. “Research. You could analyze my thighs more.”
Yoongi looked at the parabola. Then at the shorts. He wrote “NO” on the corner of Jimin’s paper and circled it three times.
“Noted,” Jimin said, grin refusing to obey the command.
When he left, he tapped the door frame twice and in the echo Yoongi thought, absurdly, face ratio 1:1.6 is probably conservative. He made a box around the thought in his head and labeled it: Do Not Touch, a category he often violated.
• ───────────── •
On their third session, Jimin arrived with damp hair curling at the nape of his neck, hoodie zipped but shorts staging a familiar rebellion. He dropped into the chair with a soft clatter, smelling like laundry, soap and a hint of court dust, and put his hands out, palms up.
“I have been a good student,” he declared. “I learned slopes. I brought snacks. I stretched.”
He did, in fact, stretch - long and luxurious, maple-gold skin and shoulder blades pressing under the hoodie, shirt riding and shorts riding higher. The lab went very quiet, which is to say, Yoongi’s brain suffered a power outage.
“Wow,” Yoongi said, so softly it almost escaped him. “Your ass is perfect.”
Jimin froze, then turned his head, slow, like something delicious was happening. “What?”
“I mean, your ass has the perfect curve.”
“Yeah? Well, you can do whatever you want with it.”
Silence cracked open, bright and precarious.
“...Anything?” Yoongi asked, careful as stepping onto ice and hoping for a miracle.
“Anyyything,” Jimin sing-songed, eyes sparkling daringly with mischief.
Yoongi reached for his notebook. He set it down. He took out a mechanical pencil, clicked it with a surgeon's calm. He opened his calculator. Some curves are too complex for simple differentiation. “Then let’s find the gradient of that curve.”
Jimin slapped the table, laughter exploding out of him so hard he almost slid off his chair. “Professor Gradient,” he wheezed. “I can’t - wait! Are you actually—?”
But Yoongi had already sketched an axis and was shading two intersecting arclike shapes with scholarly commitment. “We’d need a parametric equation,” he murmured, unbothered by Jimin cackling into his forearms. “Possibly multiple measurements. Left versus right. For accuracy.”
Jimin wiped his eyes. “What’s the slope of my left cheek then?”
“Approximately negative point six seven,” Yoongi said, deadpan, because why stop now. “Your symmetry is almost perfect, which is statistically unfair.”
“You’re such a nerd,” Jimin said, fond as if he meant something else, and Yoongi’s pencil hesitated, like even graphite could blush.
“And you’re statistically distracting,” Yoongi replied.
It turned into an inside joke because of course it did. Jimin left that day still chuckling, calling over his shoulder, “You’re coming to the game, right? For... research?”
Yoongi circled NO on the paper again, more aggressively. He also set an alarm on his phone for Saturday and labeled it “suffering (volleyball).”
• ───────────── •
The SNU gymnasium on game day throbbed with sounds: sneakers squeaked, whistles trilled, students chanted. Yoongi arrived in a sweater he pretended was armor and sat alone, clipboard in his lap like a talisman of detachment. He wrote “Observation Notes” at the top of a page to convince himself he hadn’t shown up for soft, ridiculous reasons.
The team jogged onto the court to applause. Jimin was easy to spot: sunshine grin, captain’s band, thighs that should’ve their own event permit. He bounced on his toes, rolled his shoulders, then caught sight of the bleachers. His eyes found Yoongi too easily, as if he’d been looking, and his smile turned private and feral all at once.
Yoongi looked down so fast he almost gave himself whiplash and wrote, Park Jimin – gravitational pull: immeasurable.
The game began. It was all velocity and clean lines, arcs and angles in motion. Jimin moved like a sine wave - smooth, oscillating; one moment coiled spring, the next airborne stanza. His jump wasn’t vertical so much as narrative: an introduction, a rise, a sweeping climax punctuated by the crack of his palm meeting the ball. Yoongi, to his horror, gasped out loud at the first kill.
Variables observed: velocity, symmetry, hubris, thighs (unclassified).
Instantaneous rate of change: my heart per second.
Jimin’s teammates teased, loud enough for the first few rows to hear. “Jimin-ah, your math boyfriend’s keeping stats!”
“I’m keeping a list of enemies,” Yoongi muttered to his clipboard and pretended he wasn’t pink.
Jimin served an ace that curved like an elegant proof. SNU students roared. Yoongi wrote, Jump ≈ 3.2m. Air time ≈ 1.8s. Effect on blood pressure = catastrophic. Then he wrote, for reasons unknown, thighs of a minor deity (probably Greek).
Jimin took corner after corner, staying present, staying bright, checking in with a glance after every good point like he needed a witness. Every time, Yoongi was that: witness, data collector, and person whose heart rate refused to cooperate with rational behavior.
When SNU won - thunderous, ridiculous, beautiful - Yoongi found himself still sitting, hands tight around his pen. He stood slowly, like a man recovering from a phenomenon, and drifted down the bleachers with the rest of the crowd.
Jimin got to him before anyone else. He was flushed and glowing, hair damp, jersey clinging. Up close, he smelled like effort, soap and something that could ruin someone’s GPA.
“So?” Jimin said, breathless grin in place. “Did all my angles check out, Professor Gradient?”
Yoongi stared at him for a second too long, then found his voice where he’d left it. “Empirically. Unpleasantly.”
“Unpleasant?” Jimin pouted, exaggerated, lower lip out like a visual trap. “You hated it?”
“I hated the part where cheering for you makes me a cliché,” Yoongi said. “The rest was... tolerable.”
Jimin rolled his eyes, delighted. “You’re ridiculous.” He stepped closer, the space between them collapsing like a badly constructed bridge. “What’s the equation for... this?”
Yoongi would have liked to say something normal. Instead: “You, me, and a highly unstable variable.”
“Sounds like a group project,” Jimin murmured.
“Pass or fail.”
“I’ll take extra credit,” Jimin said, and kissed him.
It wasn’t cinematic. It was better. It was a soft collision of heat and relief, laughter exhaled into the corner of a mouth, a hand curling in Yoongi’s sweater with grateful insistence. Yoongi thought, inanely, vectors align, and then stopped thinking at all.
They broke apart on a shared breath. Jimin’s eyes searched his face like he was solving for x and liking what he found. “So?”
“Positively correlated,” Yoongi said. “Extremely.”
“Nerd.”
Someone wolf-whistled, and Jimin did the thing with his lower lip again just to watch Yoongi swallow. “Walk me out, Professor Gradient?”
Yoongi sighed like a man agreeing to tax law. “Fine. But I’m carrying the clipboard.”
“Hot,” Jimin said.
• ───────────── •
After that, the math lab hours got less strange and the moods got worse in the best way. Tutoring sessions involved more learning than either of them admitted out loud. Yoongi discovered Jimin’s brain liked pictures, so he drew arcs and trajectories, turned slopes into serves and derivatives into momentum, and Jimin began to answer before the question finished asking itself.
Jimin learned to love the click of a pen before a clean line. He also learned that Yoongi’s sarcasm hid soft places like any good armor, and that he likes to flirt in puns. Which is not good for Yoongi’s heart:
“Hyung, I think I like fractions. Do you want to do some with me? You can be the numerator so you can be on top of me.”
“Did you know that the square root of all my fantasies is you?”
“You keep talking about functions Professor Gradient, but I think you just want to touch mine.”
“You’re the common denominator of all my distractions.”
“You integrate perfectly into my chaos.”
Every so often, the notebook with “Empirical Study of Park Jimin” in bold letters on the cover came out. “Purely academic,” Yoongi would say as he wrote:
Hypothesis: proximity ∝ stupidity. Confirmed. Control variable: denial. Conclusion: He’s hot and it’s ruining me completely.
“Right,” Jimin would answer, tapping the back of his pen against Yoongi’s wrist. “For research.” And his smile would tilt, and Yoongi would forget how to be mean.
Once, on a bench outside the gym, Jimin draped a thigh across Yoongi’s lap like it was no big deal and asked, “Do you really think they're Greek-statue level?”
Yoongi looked down at the muscle, the clean sweep, the curve that had launched a thousand bad metaphors, and said as honestly as he could manage it, “You have the thighs of a minor god. Perhaps not Zeus. Maybe Hermes: fast, unreasonable, a little mischievous.”
Jimin preened, then pretended not to. “You’re whipped,” he sang.
“That’s a valid vector direction,” Yoongi said, and Jimin laughed so hard he almost fell if not for Yoongi gripping said thighs.
• ───────────── •
Months later, Min Yoongi walked into a packed lecture hall, opened his laptop, and projected the week’s slides. He was two sentences into a droning explanation about partial derivatives when Slide 13 appeared, and his stomach dropped.
Empirical Analysis: Rate of Acceleration in Park Jimin’s Thighs (2025–Present)
The room inhaled as one organism. The photo - tasteful, praise all gods - was of Jimin midair, a blur of power and grace, eyes fiercer than any argument. Graphs dotted the margins. A footnote read: Data collected under duress and flirtation.
Yoongi froze. Someone in the front row whispered, “No way.”
From the back, a voice that owned his whole being: “Hi, babe!”
The students turned. Jimin was there, ridiculous and radiant, waving like he’d planned this, because he probably had. He was wearing his team jacket and the grin that could double as a legal loophole. A chorus of “awwws” rose like birds.
A student whispered, “That’s one hell of a dependent variable.”
Yoongi closed his eyes. Inhaled deeply. “That,” he said to the hall, “was for demonstration purposes.”
Jimin cupped his hands around his mouth. “You’re demonstrating how whipped you are!”
“Language,” Yoongi said weakly.
A hand shot up in the second row. “Jogyo-nim, is this... going to be on the exam?”
Yoongi glanced at the slide. At Jimin. At a hundred faces trying not to grin too hard. He sighed, resigned and a little dizzy. “In spirit,” he said. “Apply the concept to your own data set.”
The room laughed. Jimin blew him a kiss. Yoongi hovered his laser pointer over the curve of Jimin’s arc on the screen - the flight path etched in neon, impossible and true - and resumed. His voice, when it came, was steadier. Warmer.
“Now,” he said, “let’s talk about how to find the gradient of a curve.”
From the back, a stage whisper: “He’s an expert!”
“Detention,” Yoongi called without turning, but he was smiling. The kind that felt like a function approaching something infinite, something out of reach and somehow, already his.
• ───────────── •
Later, when they were alone in the lab again, Jimin nudged him with a knee. “You survived.”
“I’m changing my passwords,” Yoongi said. “All of them.”
“To what? JiminIsA90DegreeAngle?”
“Don’t flatter yourself, even if you are perfect,” Yoongi scoffed, then added, too honest, “You’re a data-driven chaos. I can’t math around you.”
Jimin kissed his cheek, then his mouth, simple and sure. “Lucky for you,” he murmured, “you’re the only constant in my equation.”
Yoongi set his forehead against Jimin’s and breathed. “Then stop differentiating me every five seconds.”
“For you, Professor Gradient,” Jimin laughed, delighted, “anything.”