Chapter Text
It had been five days since the "thigh incident" at the farm, and for Stan, every minute away from those legs felt like an eternity of deprivation. At school, they maintained the facade: intense glances exchanged in the hallway, "accidental" bumps that made the brunette break into a cold sweat, and text messages Kyle sent during the most boring classes, describing exactly what he would do to Stan if he weren't focused on the blackboard.
Stan walked into Kyle's room, dropping his backpack onto the floor, his face lit up by a victorious smile as he pulled his Biology test out of his folder.
"Look at this, Ky! An A+. I even drew the bonus Golgi apparatus the teacher asked for," Stan exclaimed, expecting, at the very least, a breathtaking kiss as an immediate reward.
Kyle, who was sitting at his desk flipping through a thick Physics book, didn't even look up from the page. He simply held out his hand, took the paper, analyzed the grade for two seconds, and placed it on the desk.
"Congratulations, Marsh. You proved you know how to memorize organelle names. But Biology is the past. Today, the subject is Physics: Gravity and Resistance Force," Kyle said, closing the book with a sharp snap that made Stan flinch.
"Physics? But Ky, I got an A+! I thought we could... you know, celebrate," Kyle stood up in an agile movement, dodging the touch and pointing to the center of the rug.
"Physics without physical education? What good are good grades if you can't handle the weight of your own decisions?" Kyle crossed his arms, a slight smirk appearing on his lips. "Take off your shirt. Now."
Stan blinked, confused, but obedience was already hardwired into his DNA. He pulled his hoodie and t-shirt over his head, revealing his broad chest and defined muscles that seemed even tighter from the accumulation of testosterone.
"What am I supposed to do?"
"Kneel right there, big boy," Kyle ordered. "Gravity is a constant force that pulls everything toward the center of the Earth. I want to see how much you can fight against it. You're going to hold a plank position. Just sustaining the weight. And I am going to be your 'overload factor'."
Stan obeyed, resting his forearms on the floor and stretching his legs, keeping his body straight as a board. He could feel his blood pumping hard, his cock already throbbing against the denim of his jeans from sheer anticipation.
"That's it... hold it," Kyle said, walking around him like a military instructor. "You know what's funny, Stan? Your muscles are strong, but your self-control is unstable. If you shake, if you touch your knee to the floor, or if you collapse, you're going to get in trouble."
Kyle then sat down delicately on Stan's back, right on his lower back, crossing his legs and opening the book again over the dark-haired neck.
"You can start counting, Marsh. If you're a good quarterback and hold me up for ten minutes, maybe I'll reward you."
"Ten minutes?!" Panic pierced Stan's voice, "Dude, I can do five at most!! Especially with you up there!"
"Weight is a vector force, Stan. P = m x g. I am your mass, gravity is pulling us down, and you are the only thing preventing a collapse. If you can't make it, we both fall. But the consequences are worse for you than for me, no doubt about it."
"F-fuck, Ky..." Stan let out a whimper as he felt Kyle's hips settling against his base. The redhead's weight made his core burn. "You... you're really heavy..."
"Don't complain to physics, Marsh. Complain about your lack of endurance," Kyle leaned forward, whispering close to Stan's ear as the brunette began to shake. "You know what's most interesting? Even with me making you plank with about 70kg on your back, you're still hard as a rock."
"Ten minutes... fuck... I... I can handle it," Stan growled, his teeth clenched, his arms starting to vibrate like guitar strings stretched to their absolute limit.
Sweat wasn't just beads now; it dripped rhythmically onto the carpet, creating small dark spots right below Stan's face. He kept his eyes fixed on a random spot on the floor, desperately trying to visualize physics equations so he wouldn't focus on the seductive sensation of having Kyle on his back.
"That's it, Stan. Focus," Kyle commented with icy calm, turning the page of his book. He felt every tremor of Stan's body beneath his own, and the sense of power was more addictive than any drug. "Static equilibrium occurs when the net force is zero. But you don't look balanced at all right now. I can feel it from here."
Kyle then did something truly cruel. He closed the book and, instead of just sitting there, he leaned entirely forward, laying his chest against Stan's bare, sweaty back. He wrapped his arms around the brunette's neck, letting his hands dangle near his face, and brushed his lips against Stan's reddened ear.
"Two minutes left," Kyle whispered, his voice vibrating straight down Stan's spine. "You know what happens if you fail now? On top of the five extra days, I'm thinking of letting you touch yourself. All by yourself."
"K-Kyle... stop talking... ngh..." Stan let out a sound that was half groan, half sob.
Stan's jeans were so tight he was certain the zipper was going to burst. His cock was being crushed against his own abdomen, and with every tremor of the exertion, the friction was a delicious agony.
"You're shaking so much, big boy," Kyle continued, moving his hands to caress Stan's tensed biceps. "Your muscles are failing. Gravity is winning, isn't it? Let your knees drop, Stan... admit that you're weak."
"N-no! I'm not... I'm not falling!" Stan gave a shout of pure effort, his arms straightening back up with a strength he drew from sheer hatred and accumulated desire.
"One minute," Kyle chuckled softly, feeling the animal heat radiating from Stan's skin. "Can you feel my heart against your back, Stanley? Hmm?"
"Kyle! Fuck! This is... this is cheating!"
"This is Experimental Physics, Marsh. There is no ideal scenario," he was laughing, "Deal with the variables."
The phone alarm didn't lie. The ring-ring echoed, and Stan didn't even know Kyle had set a timer. Even so, he kept sustaining the weight on his arms.
"Hmm... you did it," the redhead noted, pulling his arms back but remaining lying down. "You my come down."
Stan's knees hit the carpet and he practically collapsed, panting, completely covered in sweat. "Get... g-get off, Ky," he pleaded.
But the redhead, sadistic as ever, just sat up on Stan's lower back again, crossing his legs, his weight causing more friction against the hard cock. "You did well, big boy. Stop whimpering."
Stan let out a muffled groan, still desperately searching for air. "I'm... I'm not... whimpering," Stan panted, his voice muffled by the fabric of the rug. "But I deserve... I deserve your touch, Ky. I didn't fall."
Kyle let out a soft chuckle, closing the Physics book with one hand and tossing it aside. He began to trace slow circles with the tips of his fingers on the sweaty nape of Stan's neck, a caress that was almost worse than the torture from before.
"Deserve, do you? Do you think Physics gives you prizes just for following its laws?" Kyle leaned in, the weight of his body shifting slightly forward, which made Stan bury his hips harder into the floor. "You understood the Law of Gravity, Marsh. Now let's see if you understand Newton's Third Law: action and reaction."
He finally stood up, lingering on his tiptoes for a moment, then looked down at the boy there. "Stay."
Stan was entertaining himself by counting the lint on the rug when he heard the characteristic sound of a zipper being undone, the soft rustle of clothes sliding down, and he froze. The color drained from his face.
He had seen Kyle without clothes before, yes, but only as a kid, and honestly, he believed that just as he had changed a lot, his best friend had too; the freckles, for example, weren't there during childhood and only appeared after puberty.
But in his curiosity (and fantasies), he had imagined what Kyle's body would look like. He was probably a bit hairy with a small, circumcised cock, and maybe hyper-sensitive from not having a foreskin. If he was lucky, maybe he could see that Kyle also had cute little freckles on his groin…
He was salivating just imagining it.
Stan kept his face pressed against the rug, his heart hammering so hard he could feel his pulse in his eyeballs. He heard Kyle's breathing get a bit shorter, less authoritative, revealing the fragility he fought so hard to hide.
"You can look, Stan," Kyle's voice came out in a thread.
Stan pushed himself up onto his elbows slowly, a cold sweat running down his spine. When he finally looked up, the air simply abandoned his lungs.
Kyle was standing in front of him, wearing only Stan's shirt—which was baggy on him—rolled up to his waist. His pale legs shook slightly, and the freckles the black-haired had imagined so much were right there, dusting his thighs and concentrating around his groin in a way that made Stan feel like he was going to pass out from how beautiful it was.
There, framed by a dense, soft, ginger bush, was not what Stan had expected, but something that made his head spin. He vaguely remembered when they were kids, a confused conversation in the gym years ago, but seeing it now... seeing the way Kyle's body had blossomed, with a prominent and sensitive clitoris peeking out between pale folds and the volume of fire-colored hair…
It was the most sacred thing Stan Marsh had ever seen.
"It's not what you expected, but I shouldn't doubt that a little puppy like you would forgett that I have a pussy, not a 'circumcised cock'," Kyle said, his tone sounding like he desperately needed validation. "You wanted to see, didn't you? Well, here it is. My 'virgin territory'. Now tell me... Newton's Third Law says that for every action, there is a reaction. What's yours going to be?"
Stan couldn't answer with words. He just crawled on his knees, as if entering a sanctuary, until he was face to face with Kyle's intimacy. The scent was intoxicating—the same soap as always, but with a warm, citrusy edge that made Stan's mouth instantly fill with spit.
He looked up, salivating, "Kyle... can you sit down and open your legs? Please, I need to see you, man. I want to see how beautiful and unique you are."
Kyle huffed, "Hmp!" but walked backward until he hit the edge of the chair, sitting down and spreading his knees. "You can look, but if you poke me, or try to put that filthy finger of yours in, I am never showing myself to you again. Do you understand?!"
Stan stumbled toward him like a starving animal, resting his hands on Kyle's inner thighs and spreading his best friend's legs even wider. "I won't... no, no, I just... Fuck, Kyle, you're so perfect," he inhaled the citrusy air, a mix of sweat and arousal, "You're a thousand times better than Wendy."
"Don't compare me to your ex, you jerk!"
But Stan, of course, was far too enthralled admiring that vulva, hidden behind the bush of little orange hairs. Finally, he brought his index finger and thumb over, separating the lips to see how open it was, the delicate inner labia with a peach undertone, and that prominent clitoris, projecting outward like a little 'cock' itself.
"K-Kyle, I... I'd feel better if... if I used my mouth..."
A violent shiver ran up Kyle's spine when Stan's fingers, trembling and careful, parted his lips. He had never let anyone get this close; no one had seen his anatomy with such clarity and... adoration. Stan's look wasn't one of judgment or fetishistic curiosity; it was pure hunger and reverence.
"Your mouth?" He tried to keep his tone of authority, but he was so flushed the freckles had vanished from his cheeks. "You really want to... put your mouth there? You know that's where I pee from, right?"
"I got an A+ in biology," Stan whispered. "I know what comes from where. And I don't care. I want to taste you, I want to know how you react when I do... this."
Without waiting for a negative response, Stan bowed his head and blew a soft, cool breath right into the center of the "bush," making the ginger hairs flutter. Kyle let out a loud gasp, his hands gripping the armrests of the chair.
"S-Stan... wait, I don't... I don't know if..."
"Shh... let your big boy take care of you now."
He finally sealed his lips there. First, a chaste and devout kiss on the top of the vulva, feeling the texture of the hair against his lips. Then, he used his nose to part the folds, inhaling deeply Kyle's scent—which was citrusy, metallic, and intensely exciting. When the tip of Stan's tongue finally made the first contact, tracing a slow path from the base to the tip of that projected clitoris, Kyle gave a muffled shout, tossing his head back.
"Holy shit, Stan!" Kyle stammered, his hips giving an involuntary jolt forward, seeking more of the contact. "This... this is... ngh... it's-it's wet..."
"Of course it's wet, Ky. It's my tongue," Stan murmured against his damp skin, before engulfing the clitoris with his lips and sucking with absolute softness, knowing he needed to be gentle since Kyle was completely a virgin. "Just feel it. Feel how much I want you."
Kyle couldn't formulate a coherent sentence anymore. He had never used anything but his own hands (and a video game controller); a man's mouth down there was doing wonders. He was just a trans boy discovering that his body, the one he protected so fiercely with rules and boundaries, was capable of generating a pleasure that no amount of reading, no matter how intense, could ever explain.
Feeling Stan there, for real, being so good, was driving him completely insane!
"Ngh! S-Stan!" Kyle jolted in the chair, his body arching violently. The sensation of Stan's soft tongue against his hyper-sensitive skin was like an electric shock. "Fuck... this is... it's different from what I read..."
"It's better, isn't it?" Stan murmured against the wet flesh, lifting his hand and gently nudging the base of the large clitoris, "I want to worship your pussy forever, Ky... you're so perfect..."
His index finger slid along the length of the little pleasure button, touching the taut urethra and the damp slit, resting at the entrance of the vagina.
Stan felt the inviting dampness and, in an impulse of pure animal excitement, tried to slide the tip of his index finger inside that narrow, warm opening. He wanted to feel the tightness; he wanted to know what it was like inside. But the second the knuckle of his finger pressed against the entrance, Kyle reacted.
"ARE YOU CRAZY, STAN?!" Kyle screamed, his voice jumping three octaves.
In a purely defensive and clumsy reflex, the redhead delivered a sharp kick to Stan's shoulder, shoving the brunette away. Stan stumbled backward, landing hard on his butt on the rug, his eyes wide and his hand still extended in the air.
Kyle curled up in the chair, pulling his knees to his chest and covering his intimacy with the hem of his shirt, his face redder than his own hair. He was panting, his pupils dilated from sheer shock.
"I told... I TOLD you to not to put a finger in, Marsh! What is wrong with you?!" Kyle exclaimed, his hands shaking. "You think it's just like that? Walking right in? You dog!"
"Ky... I'm sorry, please, I'm sorry!" Stan raised his hands in surrender, cautiously approaching the edge of the chair. "I got carried away, I swear! It's just that you're... you're so beautiful and you were so warm, I just wanted to feel how tight it is!"
Kyle huffed, but he didn't pull away when Stan drew near. His green eyes peeked at the brunette with a mix of indignation and a vulnerability that broke Stan's heart.
"Tight? Of course it's tight, you idiot! I’ve never insert anything in there!" Kyle exclaimed, his voice cracking. "You can't just... ignore the rules of virginity! We haven't even studied dilation or the friction coefficient for this area yet!"
"Wait, anything?" Marsh asked, resting his hands on his lap. "Not even your fingers? Or, like, a deodorant?"
"What? No, Stan! Testosterone makes it tight! I take hormones!" Kyle explained, shaking his hand like crazy. "I barely have any natural lube! Nothing fits in there! You brute! You ogre! I am never letting you touch me again!"
Stan couldn't help but let out a low chuckle. Even in the middle of the chaos, he wasn't used to seeing his best friend react like this, and it was kind of cute in a way—so different from the bossy Kyle. He knelt between Kyle's legs (which were still tucked against his chest) and gently held his knees.
"Forgive me, mestre. I was a terrible little puppy," Stan whispered, kissing the scar on Kyle's knee. "I won't stick anything in. I promise. I just want you to relax. Just let me... use my tongue again? I swear I'll stay right on the clit."
Kyle looked at him for a long time. The arousal was still there, throbbing beneath the surface of the shame. He sighed, relaxing his shoulders and letting his legs fall open a bit, though he still kept his shirt pulled down.
"You're a very persistent dog, Marsh," Kyle grumbled, but his sadistic tone was slowly returning. "Fine. You can come back. But everything has a limit. Got it?"
Stan caught Kyle's hands, lacing their fingers together as he settled back into place. "Hands where you can see them, okay? I promise..."
Kyle relaxed his body against the back of his chair, his hands intertwined with Stan's, his fingers tightening as vulnerability was replaced by an electric anticipation. His legs opened up again, this time without the shock from before, but with a trembling he couldn't control.
"That's it... good boy," Kyle whispered, his voice catching as he watched Stan lean in. "You may start."
Stan didn't need another command. He dove in. This time, he ignored the slit entirely and focused all his effort on the prominent, pulsing clitoris. He engulfed it with his lips, using the tip of his tongue to give quick, rhythmic strokes while sucking with constant pressure.
"Ngh! S-Stan!" Kyle threw his head back, his hips beginning to lift off the chair in a desperate arch. "Don't stop! Fuck, don't stop!"
Kyle felt the heat rush up his legs, an unbearable pressure accumulating right in the center of his womb. His nails dug into Stan's hands, and he began to lose his mind. The "mestre" was disintegrating. His hips began to thrust involuntarily, seeking Stan's mouth as if it were oxygen.
"I'm going to... I think I'm going to... Stan!! Agh!!" Kyle screamed, his body going rigid as a spring.
Kyle's first release of pleasure was violent. He had spasms that made him almost kick the air, his vision going white as the first real orgasm of his life hit him with the force of a supernova.
He came so much, the clear fluid staining Stan's chin, while he let out sharp, desperate whimpers.
After long seconds, Kyle groaned, panting, his face covered in sweat and his legs still shaking uncontrollably. Stan lifted his face, his lips glistening, looking up at his best friend with an adoration that bordered on insanity. Stan's cock was so hard it actually ached, throbbing desperately for any touch.
"Ky... you were incredible," Stan panted, shifting his hips to try and relieve the pressure in his jeans. "Now... now can I? Please, it's been almost a week, I can't take it anymore..."
Kyle lay there for a few seconds, his eyes fixed on the wall, feeling every nerve ending in his body tingling as if he'd been struck by lightning. The sensation was... indescribable.
Far better than any paragraph in a book. But as the air returned to his lungs, Kyle's sharp mind returned with it.
He looked down and saw Stan. Poor Stan. The brunette was kneeling, his face glistening and his cock hard as a stone, begging for a relief he saw as an earned right.
Kyle let out a soft chuckle, wiping the sweat from his forehead with the back of his hand, reclaiming that aura of authority that Stan both feared and loved.
"Can you what, Marsh?" Kyle asked, his voice still a bit husky but dripping with renewed malice. "You think just because I had a successful demonstration, you get a free pass?"
"Kyle, for Fuck’s sake! I almost had a heart attack just watching you!" Stan whined, his hands going to his own zipper but stopping halfway upon seeing the redhead's stern look. "My balls are blue, Ky! Literally!"
"Biology says you'll survive a few more days," Kyle adjusted his posture, ignoring his own nudity with a new confidence. With his foot, he pushed Stan's chest back, forcing him to maintain his distance. "You were a wonderful assistant today, Stan. But you forgot the main rule."
"Rule? What rule?!"
"The professor is the one who gets the laurels of the research. The assistant merely observes," Kyle tilted his head, his ginger bush still damp and his pale legs stretched out. "You had the privilege of being the first man to see and taste me. That should already be reward enough."
Stan let out a whimper of pain and anguish. "Ky... you can't be serious..."
"I am. In fact," Kyle gave a sadistic smile, stepping away from the chair and picking up his sweatpants from the floor, "Since you were a little 'invasive' with that finger, I've decided your denial time didn't reset. It just increased. Three more days, Marsh. For attempted insurrection."
Stan buried his face in his hands, huffing in frustration, while Kyle put on his pants with an irritating calmness.
"Now, get up," Kyle ordered, patting Stan's cheek. "Go to the bathroom, wash your face, and get my taste out of your mouth. We're going out, I want to eat ice cream."