Rumble of Thunder

by Borealium

First published

Rumble and Thunderlane have had a relationship that goes beyond familial for some time. They're yet to go all the way, though - until now.

Home from a long and tiring gym session, Thunderlane can't wait to check in with his little brother and have some alone time with him. One thing leads to another, and before long they're both very much enjoying each other's company.


All characters involved are 18+ in this story.

Gay | Incest | Curvaceous femboy (Rumble) | Lotta muscle, very tall (Thunderlane) | Large & hyper endowments, excessive cum | Anal | Oral


Cover art made from two pictures, by DreamCasterPegasus and ChainChomp2

Opening Up

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Boom. Boom. Boom

The sound of heavy footfalls reverberating through the house told Rumble that his older brother was home from the gym. He could hear him grumbling for the umpteenth time.

"Dammit, gotta get this doorway widened one of these days."

Said doorway was a good two feet across, but Thunderlane had to step through sideways and duck his head down to get his enormous body through it - and even then it was a squeeze, his slab-like pecs and obscene crotch bulge scraping against one side, and his perfectly rounded, firm glutes pushing against the other side.

He pushed his bulge in with his hands; it seemed to resist him almost instantaneously, swelling out obscenely and pushing his hands back again. Fighting the intense stimulation and pushing harder, he just about got his junk through, along with the rest of himself.

"Ah."

He exhaled and relaxed, his broad chest falling with his breath. Rolling his shoulders, he threw his backpack against the wall and stomped upstairs. He was home later than usual today, the diminishing light of late afternoon shining across the floor from the open windows.

"You home, little bro?"

"Uhuh!"

Rumble was laying on his stomach on his bed, only in boxer shorts, flicking through one of his brother's fitness magazines. In the past he might have rushed to get dressed before his brother came in but these days he didn't worry about that. He and his brother had gotten very close, perhaps - he thought to himself - in more ways than one.

So, he just stayed in his underwear, one lithe calf crossed over the other, his large and curvaceous behind unashamedly rising above his wide, flaring hips.

Despite being brothers, the two of them were virtually opposites physically. Thunderlane, his seven-foot body packed with brawn, shoulders wider than most doorways, biceps comparable to half-watermelons capping his thick, defined upper arms, was in complete contrast to his younger sibling.

Rumble was quite slender, 5'7 tall with faint muscle definition, but beneath the waist his body was decidedly feminine and very curvy. Expansive, curving hips two feet across supporting a decidedly rotund, verging-on-enormous derriere that extended a good six inches from his back, and thick, creamy thighs that curved gradually inward to his knees. As distinctly un-masculine as his body was, Rumble was fond of it. He wasn't exactly a macho stallion anyhow. And if his suspicions were correct, Thunderlane rather appreciated his physique as well. One thing they did have in common, though, was being well-endowed. Rumble's foot-long shaft was very impressive in its own right, but still looked small compared to his brother's three-foot monster that was as thick as Rumble's thigh when it was hard - and knowing his brother, that was most of the time.

It was one of Rumble's guilty pleasures to kneel by the bathroom door, ear against it, every morning when his brother was in the shower. Rumble thought it was adorable when Thunderlane tried to surreptitiously pleasure himself without his brother knowing, but his dick and his hands were so big that when he really got into it, the sound was unmistakable and quite impossible to cover up. This morning had been a particularly enjoyable audial session. Rumble listened intently as his brother whimpered and whined, restraining himself from crying out as he pumped his monolithic member with wild abandon. Then, as the climax came, he groaned through gritted teeth as thick ropes of cum splattered loudly against the tub, splashing against his feet and nearly blocking the drain. Rumble very nearly joined his brother in climaxing but as usual managed to hold himself together and disappear before his brother came out.

Rumble's daydream was interrupted by the floor shuddering as Thunderlane stomped up the stairs. He opened the door, ducked slightly, and sidled through, pulling off his t-shirt as he did so. Raising his head back up as he discarded the bundle of cloth, his eyes automatically locked on to Rumble's big behind, and the bulge in his gym shorts began to expand, snaking around inside his underwear and taking up every available inch of space. Much like Rumble considering covering up, Thunderlane would once have been deathly embarrassed of such an explicit and obvious show of arousal caused by his brother and would have done everything in his power to conceal it. But now? Eh, what the heck. Let's see where this goes.

"Hey, Rumble. Good read?"

Rumble rolled onto his back and sat up, propping himself up on the pillows.

"Hi. Yeah, you could say that."

Judging by the big hard-on Rumble was sporting, it sure was a good read. Packed to the brim with big, sweaty stallions working out, flexing and posing, it was right up Rumble's street. But as big and beefy as some of the mag's models were, they all paled in comparison to the demigod stood before him now.

"Jeez, Thunder. Why don't you give the editor a call or something? They'd stick you on the cover in a flash... no pun intended."

Thunderlane laughed heartily and sat on the bed next to his brother, who scooted across to make room for his bigger brother. Thunderlane swung his legs up and laid back, putting an arm around him and nuzzling the side of his face.

"Kinda you to say, but that ain't for me. Don't wanna be the centre of attention, there's only one stallion I want ogling me."

Rumble smirked and reached out with one arm, tracing a line with his finger up between his brother's big, rock-hard abs. He couldn't help but notice Thunder's bulge throb a little larger as he touched him.

"Well there's enough of you for the whole damn town to ogle, big guy."

"You're one to talk, bubble butt!"

"Oh, you did not go there! Yours isn't exactly petite either!"

"Been checking it out, huh? Can't blame ya for that."

They couldn't help but laugh at one another. It soon died down, and Thunderlane spoke again.

"Honestly though Rumble, I don't wanna sound weird but... you do have an amazing butt."

A rosy redness tickled Rumble's cheeks.

"Thank you, that's sweet of you to say. Yours is pretty damn impressive too."

It was Thunderlane's turn to blush. His butt was pretty darn big as well, even on his massive frame. Unlike his brother's though, there wasn't much jiggle - it was mostly muscle, but still had hint of softness to the touch. Jeez, just talking about his brother's body was really getting him going. Any minute now his gym shorts would start to tear from the immense pressure his immense package was exerting on them.

"Gah, the things you do to me!"

He stood up briskly and bent forward, inadvertently giving Rumble a first-class view of his prodigious rear packed into briefs as he shimmied his shorts down his musclebound legs. Slipping them over his feet, he stood up and looked down to see that his underwear wasn't faring much better. Did he dare?

He looked over his shoulder with his thumbs hooked into his briefs, locking eyes with his brother.

Rumble was sat up on the edge of the bed now, his hungry gaze was enough of an answer. Without thinking twice, he hiked his underwear down as well. Freed from its cloth prison, the comparatively cool air of the room felt pleasant for his warm, pulsating shaft. By now, it was rock-hard and nestling between his huge pecs, the head bobbing in front of his mouth. He'd sucked it himself plenty of times, and quite a few lucky mares (and a handful of stallions) had the privilege of doing the same. His brother? Nope. Not yet, anyway. He turned, his length swaying slightly and coming to rest a second or two after the rest of him.

And there he was; naked - and hard as steel - right in front of his brother.

"Sweet Celestia, you're perfect. So, you... gonna let me suck that thing?"

Thunderlane's cock replied with a lurch, a big glob of precum splurting out and splattering on Rumble's legs.

"I'll take that as a yes."

Brotherly Love

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Loud sucking and slurping sounds accompanied Rumble's great oral effort on his brother's gigantic cock head.

Sat on the end of the bed, arms propped up behind him, Thunderlane watched with aroused fascination as his flare was orally worshipped and thoroughly service by Rumble's mouth.

Delicately lashing its crown with tender licks, engulfing its entirety around his lips and forcing his tongue into its slit, kissing it passionately while massaging the shaft below it; Rumble was really getting into it.

Rumble was sat in Thunderlane's lap, facing him, using his brother's enormous thighs as a seat. Thunderlane's rock-hard pillar of flesh rose between them, Rumble pulling it in to his eager mouth. Their balls were mashing together between their legs as Rumble pressed in to give the midnight-black monolith before him his full appreciation. With every hard suck or squeeze, Thunderlane tensed and his enormous muscles swelled along with his erection which couldn't help but deliver a mouthful of pre into the ravenous mouth of its benefactor.

By now, the flow of pre-cum from his slit was constant - a visceral plea from his enormous, sloshing balls angrily demanding that they be allowed to expunge the enormous load bloating them incessantly. How could he refuse them? They'd been getting bigger and bigger and bigger, and with their expansion the desire to orgasm and empty them had only grown more pressing. He laughed internally to himself. Okay, perhaps empty was a little optimistic, that would need more than just one orgasm.

Rumble could tell his brother was getting close. He could hear the churning, roiling protests from the immense bowling ball-sized testes below them both. He tightened his grip and stroked harder and faster, his free hand reaching down to fondle and grope the giant gurgling gonads which would soon be convulsing, straining to perform their sole function.

Barely cogent from the ocean of pleasure bathing his mind, Thunderlane could only respond by reaching down to his Rumble's lower back and forcefully grabbing two handfuls of thick booty meat. Even in the palms of his big hands, there was plenty to spare.

"Gonna - guhhhnnn..."

Thunderlane could hold back no longer, he was swimming against the tide. That tide just happened to be white and sticky, as his brother was about to find out. He squeezed the globes of flesh in his hands and reflexively pistoned his hips upward half a foot, jamming his broad cock head into Rumble's throat just in time to receive the monumental load that was stretching out his nuts.

He growled deeply in his throat and screwed his eyes shut as the orgasmic sensation spread from deep within his groin all the way up to his quivering flare, and when it reached the tip, which was forced to expand to make way for the oncoming flood, he cried aloud as a thick, potent blast of sperm forced its way down Rumble's throat before he could even swallow - bit swallow he soon did, the next vast load of off-whote cream blowing out his cheeks and dribbling down his chin. Shoom, gulp, shoom, gulp. Thirty seconds of swallowing complete mouthfuls of liquid love before Rumble pulled away for a breather, still kneading the bowling balls in his hands.

Thunderlane seized his thick cock in both hands, steadying the base with one and jerking off the top half with the other, painting his brother's face and chest with the last two or three powerful spurts of jizz before the river became a stream, and then a trickle. Shivering in the pleasure of afterglow, Thunderlane lifted his dick up to his mouth and swirled his tongue around and over his head. It was very sensitive after his recent orgasm, but he could tell his dick wasn't done yet - let alone his balls.

He slowly but surely came down from his high, smirking at Rumble who looked pretty pleased with himself.

"Been practising?"

"I guess ya could say that."

Like his brother, Rumble did enjoy more than a little self-fellatio when he was alone.

"Heh. Welp, I'd better return the favour, huh?"

Thunderlane took Rumble's waist in his hands, lifting him up without difficulty.

"Wha-woah!"

Thunderlane stood up beside the bed and gently tossed his brother onto it, then knelt in front of him, pulling his boxer briefs down and off his legs. He surveyed the foot-long length in front of him and licked his lips.

"Been waiting a while to do this. And I guess you've been waiting a while to get it too."

Rumble could only bite his lip and smile adorably, his insurmountable erection like a heart on his sleeve.

Not one to beat around the bush, Thunderlane dove in. He pushed his hands under his brother's back and held him from behind as he went to town on the light-grey length stretching out to meet him. Twelve inches was certainly an impressive size, but Thunderlane's mouth was big enough to take it all with the tip just tickling the back of his throat. He casually slid his head backward and forward, maintaining an overpowering suction on Rumble's dick.

"Unh... ah... y-yeah..."

Words failed Rumble. That was sign enough to Thunder that he was doing a pretty good job. So, he took it up a notch. He brought his hands around from Rumble's back and brought them into play as well, one cupping Rumble's balls and the other firmly grasping the lower half of his penis. With a few twists, squeezes and strokes, combined with his incessant oral efforts, Rumble was forced right up to the edge rather quickly.

"Aaah!"

He cried out as his cock lurched hard in his brother's hand, fattening as it forced his load up and out, coating Thunderlane's tongue and flowing down his throat. He could only moan as the orgasm washed over him, each spurt no less pleasurable than the last. Thunderlane greedily swallowed every last drop as each rope raced out to fill his maw.

Rumble continued to convulse slightly as he rode the wave back down to pleasant afterglow, panting quietly as Thunderlane drew back and swallowed once more.

"Mm, think I gave you a pretty good run for your money. Y'enjoy that?"

"Mhm."

"Great. Wanna... go a little further? I mean, if you're up for it."

Rumble giggled as Thunderlane twiddled his thumbs.

"Hm, lemme think about that, uh - yes."

Rumble turned over onto his stomach. Thunderlane got his first view of that incredible booty unclothed - and what a view! It looked, well, perfect. Big, supple, round, wide; a butt without equal as far as he was concerned. He drew forward onto the bed and got down on all fours, lining his head up with the bountiful behind underneath him. He slowly lowered his hips, one hand steadying his length and keeping it on target.

Rumble's ass was so soft that Thunder's head parted its ample cheeks with virtually no effort. Further in, though, it was incredibly tight. Thunder was a little anxious but it was Rumble that spurred him on.

"Fff-fuck, keep going."

He pushed with his hand and his hips together, gradually overcoming and widening the opening he was fervently assaulting. His brother's moans rose in pitch as the first inch cleared his back door. It was coping surprisingly well, adapting quickly to the sheer girth of the black monolith demanding entry - the cascade of warm, creamy pre was definitely helping too. Before he knew it, a foot of his throbbing manhood was lodged inside. Rumble was in bliss, only partially cogent but thoroughly enjoying himself. Thunderlane chose not to go any further as he only got girthier towards the base of his shaft and the going was getting more difficult. That wouldn't be a problem, though - the first foot was proving to be more than enough for both of them to get satisfaction.

Thunderlane slowly drew back, then drew forward slightly more quickly.

"Aaaah, ah!"

Each motion in either direction drew cries of pleasure from them both. Thunderlane picked up the pace, slowly but surely, until he had a good rhythm going. He huffed and puffed with each push of his hips, Rumble's big ass jiggling and shaking with every thrust. Faster and faster, their intimate lovemaking audible from quite some distance away - and neither of them could care less. Thunderlane plowed on with wild abandon, reaming Rumble's rear passage feverishly.

Only a few minutes in, the overwhelming tightness combined with the soft plushness of that sublime butt pushed Thunderlane over the edge.

"Nngh, ffugh, c-cumming!"

He thrust in as far as he dare, exploding deep inside Rumble. A gout of jizz spurting forth and almost immediately pushing out his brother's stomach. Thunderlane gripped handfuls of bed sheet as he came again and again, thick blasts of cum blasting into the writing Rumble. Despite an orgasm not long ago, his big, fat balls were relentless in their stuffing of the little grey stallion still filled with inches of hard, thick meat. Rumble's shaft had been stimulated by the rubbing of the sheets against his hard length pinned beneath him, and he came not long after, his own sizeable load loosing and soaking the duvet with a series of potent discharges.

After a few more big spurts, things began to calm down. Thunderlane almost collapsed onto his brother but managed to hold himself up as he pulled his semi-hard shaft out of its hidey-hole. Then he slumped down beside his brother, one arm hanging off the bed. Rumble slowly turned over and surveyed his swollen cum-belly, as well as the large damp area his own release had created. In no mood to change the bedding now, he just collapsed onto his brother's wide, burly torso and drew his legs up, head nestled between two pillow-like pecs.

"Mm, have fun?"

Thunderlane smiled lazily.

"Plenty."

As the evening sun began to disappear, the room darkening, the two of them drifted off together.