Little brother gets big

by pkak2k12

You (a muscle stud) are home alone with your 20-year-old younger brother (Joey). After a good fap in the shower you hear a crash coming from downstairs. What is he doing?

1,596 words Added Jul 2022 28k views 5.0 stars (13 votes)

Plausible Size Difference

M/M

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You hurry downstairs, hearing the crashing noise coming from the kitchen. “Joey!” You yell, knowing it’s your little brother. You had just finished a shower, enjoying the privacy as you fantasise about your hidden lust for bigger stronger men. For you, that was difficult, being 6’6’’ and 300 pounds of muscle. Living at home for a few years longer had left you with plenty of time to work out at the gym, and it really had come through. Even your little brother, though a handful of years younger than you, was following in your footsteps.

Clad in just your boxer shorts you hurry down the stairs. If Joey is hurt, you are there to the rescue. If he is messing around, you’re going to show him how a big brother scolds a little brother. The thought of it makes your thick semi-hard cock twitch, mainly from imagining it from Joey’s perspective, threatening to grow to its full 10 inches.

However, opening the door to the kitchen you see a completely different scene. Joey, your sandy haired little brother, with his boyish looks and slim athletic frame, stands in the middle of the kitchen beside a completely destroyed dining table. Something has happened to Joey though. His face still looks as youthful and good looking as normal, the mild smattering of freckles on his lightly tanned skin, but the rest of him seems to be huge. Beforehand, he was maybe 8 to 10 inches shorter than you, but you find yourself tilting your head up a little to look him in the eye.

Also, he seems to be super jacked. His muscles are swelling before your eyes, the cotton shirt straining as you can hear the threads beginning to give. Where there was a lovely swimmer’s frame, two huge pecs, as big as his head, are forming, beneath which six, no eight, cobblestone abs are becoming more and more defined. His arms push out a little as his growing biceps fight for space, tearing the short sleeves away.

“B-bro.” Joey looks over at you, his eyes fraught with worry, almost paralysed in shock. “I don’t know what’s going on. What should I do?”

You watch on in awe, seeing that it’s not just your little brother’s upper body that’s affected. His shorts appear to be struggling with the trunk-like thighs, purely muscle, as well as ready to explode from the sheer enormity of the bulge between his legs and stretching around his hip. It looks as thick as his forearm, which is huge in itself, and probably not even hard yet. There is the sound of ripping as Joey turns a little. A huge bubble butt has broken the threshold, his thick toned cheeks each a huge handful. He always had a nice looking ass, but now it was even more amazing.

“I don’t know, just don’t panic,” you tell your little brother as well as yourself. He seems to be gaining inches everywhere; height, muscles, groin, feet. All of him is expanding into a mountain of manliness. Your dick strains against your boxer briefs, begging you to grab it or him.

“I feel so hot.” Joey runs a hand through his sandy shoulder length hair, even his hands have grown into powerful thick digits that could crush coal into diamonds. His other hand reaches to his eight-pack, rubbing them and brushing the top of his bulge. “Ohh…” He lets out a small moan as you see the bulge reaching around to his hip throb, resting over the two huge orbs, each one bigger than your fist.

“Quick, get into the living room,” you tell your little brother, though you can’t really reason calling him that anymore. “There’s more space there.”

Joey nods as he takes two powerful strides across the room. He looks to be a foot taller than you, maybe more, as his shirt gives way. The two huge pecs, smooth and hairless, thrust out like an open drawer from his torso. You watch in awe as he struggles to get through the now small doorway, his tiny nipples getting erect as the doorframe gets sandwiched between his pecs.

As Joey gets through the doorway, you see he’s taken a chunk of the door frame with him, destroyed by the strength of this near 8 foot tall titan. You watch the remnants of his shirt fall off, showing his chiselled back to you. Completely hairless, it ripples with muscles upon muscles. He’d put Mr Olympia contestants to shame with such definition, each step rippling with power. Beneath that, his massive bubble butt seems to keep on expanding, resting over the thick thighs made completely from raw strength and power, his calves supporting this immense frame, down to the feet that definitely need custom shoes.

Joey is panting as you enter behind him and the next RRRRRIIIPPP happens. The shorts, originally stretchy and probably baggy, are completely destroyed as they can no longer hold the manhood of your younger brother. Still flaccid, his shlong droops over the now basketball sized nutsack, which you notice is clean shaven, the head still covered in foreskin hovering around his knee. It makes you wonder how hung he was before the transformation.

“Okay, sit on the couch.” You instruct Joey, trying to put brotherly instincts first, no matter how difficult it is. The giant muscle man obeys, taking a seat at the frame creaks under his weight. You wonder how much he must weigh, could he be twice, maybe three times your own impressive weight?

“What now?” Joey asks you, still taking heavy breaths. You can see his cheeks are flushed, his hands subconsciously move to his chest and cock, the latter twitching and beginning to inflate to even bigger than its already ridiculous size. He’s definitely horny.

“We take care of this,” you tell him as you straddle his swiftly inflating cock, leaning your chest against his. Joey lets out a small moan as your hands begin to play with his now minute looking nipples, your nose taking in the scent of his manly aroma whilst his dick continues to throb and grow beneath you. You’re surprised as it touches your taint and back of your own toned ass, then starts to push you up from the floor.

“Fuck.. big bro.” Joey’s words are breathless. “More, please.” You can feel his muscles tightening, but also expanding, in your grasp. The cleft between his pecs grows deeper as its enticing cleavage makes your 10-inch cock drool pre into your shorts. Your seat upon Joey’s cock elevates you up some more as you glance behind you. The huge pink head, now unsheathed, is in line with his chin.

“Here…” Joey takes one of his massive hands and grabs the back of your boxer briefs, pulling them as they tear away from your smaller form as if they were made of tissue. His biceps, bigger than your head at this point, press his pecs closer as he silently pleads for you to use them.

Not wasting any time, your thick 10 inch rod pushes between the pecs. There is some resistance from the huge muscles, but enough space for you to thrust in and out, in and out. Joey moans again as you pick up the pace, the sensation apparently doing as much for him as it does for you. “B-bro.” He mumbles as you begin to smell a very strong whiff of musky manliness. Glancing back you see a torrent of pre leaking from the gigantic manhood you’re sitting on, the constant dribble beginning to make a pool on the carpet.

You can’t hold it any longer as you let out a primal grunt, blowing a massive load between your younger brother’s huge muscle tits. You spot a small amount of it escapes the top, landing on the shelf of buff boy and narrowly missing his face. You find you’re also breathing heavily as the post nut euphoria begins to wave over you.

“Bro, I need it.” Joey’s eyes plead to you, glancing over his massive pecs. One of his hands struggles to get even half of his mighty girth at this point. “Please,” he begs.

You turn around on your cock seat, coming face to face with the huge mushroom-shaped head of Joey’s cock. You begin to lick it, reaching for the tip as you lap up the potent precum. It tastes amazing, each mouthful enticing you to drink deeper from the wellspring of his fertile shaft. With your licking, body grappling, and his huge hands pumping, it is only a matter of minute before your massive little brother yells, his bellow like a call of an ancient mating cry, and the ceiling is coated in a thick layer of cum. Blast after blast keeps escaping, as your mouth is filled and your face pushed away, your senses filled with the sheer strength of his cum.

Joey relaxes as you slip off of the still half-mast monster cock, collapsing into the pool of pre and blotches of cum drip from the ceiling. “That was amazing,” your younger brother says, now easily over ten feet tall, and everything with bigger proportions than before you started. You’re pretty sure you saw his dick twitch as his head and shoulders inch towards the ceiling. “Can we do that again?”