The front door slammed open. Rain still hammered the porch behind him.
I was halfway down the stairs when I saw him.
Ryan.
My brother.
Except the guy filling the doorway wasn’t the lean twenty-year-old who’d left for college last fall. This one had to duck under the frame. Six-five at least. Shoulders so wide the wet T-shirt clung to them like a second skin. Dense muscle stretched the fabric. Rain ran down the thick column of his neck and disappeared into the dark forest of chest hair visible through the soaked white cotton. His arms were ropes of vein and meat. Even through the wet shirt I could see the dark hair in his pits.
The smell hit me first — rain, leather from his duffel, and underneath it something heavier. Musk. Male. Thick.
“Nate.” His voice was lower than I remembered, rough like he’d been growling all semester. He dropped the bag and opened those huge arms. “C’mere, little brother.”
I stepped into him. My face pressed against the hard plane of his chest. Heat poured off him. Under the rain I caught the sharp, animal scent of his pits — sweat and something richer, almost sweet. His arms locked around me and squeezed. My ribs creaked. I felt the solid weight of him… and the way his cock pressed heavy against my stomach through his jeans. Soft and already huge.
“Holy shit, Ryan—” My voice cracked. “What the fuck happened to you?”
He laughed, that deep chesty sound vibrating through both of us. “Experimental compound. Biology majors. Muscle, hair, the works. Lasts about forty-eight hours per dose.” He pulled back just enough to look down at me. His eyes were darker. Hungry. “Parents gone till Sunday, right?”
I nodded, throat dry.
“Good.” He grabbed the duffel like it weighed nothing and started up the stairs. “Come on. I need to get out of these wet clothes.”
I followed. My eyes stayed locked on the massive curve of his ass in those soaked jeans. The fabric clung to thick, hairy thighs. Every step made the muscle roll and bounce.
In his old room he dropped the bag and peeled the wet shirt over his head in one motion.
Chest like a wall. Dense, heavy pecs covered in thick black hair that ran in a dense mat down to his navel and lower. Shoulders rounded with muscle. Arms so thick the veins stood out like cords. His pits were dark caves of dense, matted hair, still damp. The smell that rolled off him when he lifted his arms was pure concentrated male — sweat, musk, something almost yeasty and thick.
My cock twitched hard in my shorts.
He shoved the jeans down without ceremony. No underwear. His cock swung free.
Nine inches soft. Thick as my wrist already, heavy, the head broad and dark. A thick vein snaked up the underside. The shaft was covered in the same dense black hair that blanketed his thighs and the heavy sac underneath. His balls hung low and fat, the size of tennis balls, covered in that same coarse fur. They shifted with the weight when he stepped out of the jeans.
I stared. Couldn’t help it.
Ryan’s low laugh rolled through the room. “See something you like, little brother?”
I jerked my eyes up. “I—fuck. You’re just… big.”
“Yeah.” He scratched absently at one dense pec, fingers disappearing into the hair. “Compound does that. Muscle. Hair. Cock. Libido.” He bent, dug a thick protein-style shake bottle out of the duffel, and cracked the lid. The smell that hit was rich, creamy, almost salty — like someone had reduced a dozen loads down to pure heavy cream and left the musk in. “Gotta keep dosing or it fades. You want a sip? You’ll feel it.”
He’s my brother. This is wrong.
My hand still reached out.
I took the bottle. The liquid was thick — almost viscous, coating my tongue like warm, salty custard with a darker, meaty undertone. I swallowed. Heat bloomed in my gut immediately.
My cock thickened in real time. I felt it push harder against my shorts, the head swelling, a slow heavy pulse starting at the base. My balls drew tighter, then felt heavier, fuller, like they were already starting to hang lower. Across my chest a sudden prickling heat spread. I looked down and watched dark hairs push up through the skin in real time — first a few, then dozens, sprouting thick and coarse across my pecs and down toward my stomach.
Ryan watched me, that half-smile curling his mouth. “There it is. Feel it?”
I nodded, swallowing hard. My pulse was in my throat and in my cock. I couldn’t stop looking at the way his soft nine inches hung, the thick head already gleaming with a bead of clear fluid.
He noticed. “You’re staring at my cock, Nate.”
Shame burned up my neck. “I’m not—”
“You are.” His voice dropped lower, teasing. “Been staring since I walked in. Looking at your big brother’s heavy dick like a hungry little slut.” He stepped closer. The heat of him washed over me. That pit-scent thickened. “It’s okay. Compound makes everything feel better. Even looking.”
My cock was fully hard now, tenting my shorts obscenely. New hair still prickled across my chest. He’s my brother. This is wrong. But the thought felt thinner already, drowned under the slow throb between my legs and the way his massive body filled the space.
Ryan lifted both arms, laced his fingers behind his head, and stretched. His lats flared. His chest expanded. Those dense, matted pits opened right in front of my face. The smell hit like a fist — thick, sharp, pure masculine musk layered with sweat and the faint metallic edge of the compound.
“Go on,” he murmured. “Sniff it. I know you want to.”
I shouldn’t. He’s my brother.
My face was already moving forward. I pressed my nose into the damp, coarse hair of his left pit and inhaled hard. The scent flooded me — sweat, skin, that heavy male musk that made my cock jump and leak.
Without thinking my tongue dragged through the hair, tasting salt and heat and something richer.
Ryan’s low, sexy laugh vibrated through his chest.
“That’s it. Good boy. Now say it. Tell me what you’re smelling while you lick your brother’s stinking pit like the little faggot you are.”
My face burned. My cock throbbed so hard it hurt. “Your pits… they smell like sweat and musk… thick… fucking male…”
“Louder.”
“They smell like a real man’s pits,” I rasped, tongue still dragging through the wet hair. “Heavy. Dirty. Makes my cock leak.”
“Good boy.”
A thick string of precum oozed out of me, soaking through my shorts. Ryan’s cock, still soft but heavy, brushed against my stomach as he shifted. I looked down. A clear, thick strand of precum stretched from the broad head of his nine-inch soft cock to the wet spot on my shirt. It glistened.
My mouth watered.
I dropped to my knees.
Didn’t touch him. Just stared. His cock hung right in front of my face, the heavy shaft still mostly soft, the thick head dark and leaking another slow bead. The smell of him was stronger here — musk from his balls, the clean-sweat scent of his crotch, the faint salt of precum.
Ryan looked down at me, voice almost fond. “I knew you were a fucking queer, but I didn’t know you were a depraved little faggot.”
The degradation lit me up. Heat flooded my face, my chest, my leaking cock. New hair still spread across my pecs in dark, coarse patches.
“Smell them,” he ordered quietly. “Acknowledge your brother’s heavy balls.”
I leaned in. The scent was thicker here — warm skin, dense hair, that rich musk that made my head spin. I pressed my nose against the heavy sac and inhaled deep. “They’re… big,” I whispered. “Heavy. Fuck, Ryan—”
“Good boy.” He grabbed the second shake bottle, cracked it, and held it to my lips. “Open. Drink the whole fucking thing.”
I opened. He pinched my nose shut with two thick fingers and poured. The liquid was even thicker this time — heavy, creamy, coating every surface of my mouth with that salty-sweet, almost meaty concentration. I had to swallow or choke. It went down hot and viscous, leaving a slick film on my throat.
The effect was instant and harder.
Fire raced through my veins. My cock surged, thickening and lengthening in real time, the head pushing out of my shorts as it grew. More hair erupted across my chest in visible waves — coarse, dark, spreading fast down my stomach and over my thighs. Muscle packed onto my frame in rolling waves. My shoulders broadened. My balls felt suddenly heavier, fuller, pulling downward with new weight. My voice, when I gasped, came out deeper.
I looked down at myself in shock — twink body gone, replaced by obvious dense muscle under thickening fur, my cock now a thick 7.5–8 inches and still leaking.
Ryan watched, eyes dark, and chugged a bottle of his own in three long swallows. His body answered even harder. Muscle ballooned. His already massive frame packed on more dense mass — chest, arms, thighs swelling until he had to be pushing 300 pounds of solid meat. His cock thickened and lengthened in front of my face, the soft nine inches becoming a heavy, veined 11+ inches that hung even lower, the head broad and dark, a thick rope of precum already dripping. His balls swelled heavier, the fur on them denser.
He flexed. Pecs jumped. Arms curled. The muscle under all that thick black hair rolled and bounced. “Look at you,” he growled, voice pure gravel. “My little brother turning into a hairy fucking stud. And still on your knees staring at my cock.”
I stripped. Clothes felt wrong on the new body. My own chest was already furred in thick dark hair, abs visible under it, cock standing thick and wet. The shame was still there — he’s my brother, this is wrong — but it was drowning under the raw need. He’s hot. He’s hung. That massive cock is leaking for me. I need it.
Ryan had six more bottles lined up. He stepped closer, the heavy 12-inch cock — still growing — brushing my lips. The broad head painted them with thick, clear precum. The smell of it, of him, of the musk pouring off his body, short-circuited whatever was left of the conflict.
He’s hot. He’s hung. He’s muscular and hairy and I need his cum.
I opened and took him.
The weight of that cock on my tongue was immediate — thick, heavy, the skin hot and velvet over the dense core. I pushed forward, choking myself on it, the broad head punching into my throat. My new deeper voice gagged wetly around him. I fucked my own throat on it, desperate, hands braced on those massive hairy thighs, nose buried in the dense bush at the base. The taste of his precum flooded me — salty, rich, endless. Spit ran down my chin. My own cock leaked steadily onto the floor.
Ryan’s hand settled heavy on the back of my head. “That’s it, you depraved little faggot. Take your brother’s cock. Choke on it. I knew this is what you needed.”
I deep-throated him harder, throat convulsing, tears streaming, the thick shaft filling me completely. The stretch burned in the best way. His balls, heavy and furred, slapped my chin with every thrust I forced. The scent of him was everywhere — pits, crotch, the clean sweat of all that new muscle.
He came with a low, guttural growl. The first pulse was massive — hot, thick, rope after rope of heavy cum blasting straight down my throat. I swallowed desperately, more than a cup of it, the volume almost too much. It kept coming, filling my mouth, leaking out the corners, running down my chin in thick white strands. The taste was pure concentrated male — salty, creamy, addictive. My new deeper voice moaned around his cock as I drank it.
When the last pulse faded I pulled off, gasping, cum still oozing from my lips. My own voice shocked me — lower, rougher, sexy. “Fuck… it tastes amazing.”
Ryan leaned down, massive body folding, and kissed me hard. His tongue shoved into my mouth, licking the cum off my chin, off my lips, feeding it back to me in a deep, filthy kiss. The taste of both of us mixed. My cock — untouched — jerked hard and I came, a massive load of my own, thick ropes painting the floor between us. Not as much as his, but still huge, pulsing for long seconds.
Ryan broke the kiss, scooped a thick strand of my cum from the floor with two fingers, and pushed them into his mouth. Then he kissed me again, feeding my own load back to me. I swallowed it greedily.
He pulled back, breathing hard, that heavy 12-inch cock still mostly hard and shining. “Effects only last forty-eight hours, little brother. We got six more special shakes. Three each.”
We split them. Chugged them standing there, naked, hairy, still leaking. The burn hit harder this time — muscle packing on in rolling waves, hair thickening, cock and balls stretching with heavy, aching growth. My body densed out further. Ryan’s frame swelled even more, the dense muscle under all that fur becoming almost cartoonish in its mass.
We staggered to the bed. He spooned me from behind, that still-hard cock resting heavy in the now extremely furry crack of my ass. The weight of it, the heat, the way his massive hairy body curled around mine — it felt right in a way that should have terrified me. Instead I just pushed back against it and let the exhaustion take me.
