Seedmaker: Galactic Stud
Copyright© 2025 by Gigi Potemkin
Chapter 1
Erotica Sex Story: Chapter 1 - The Seedmakers are a race of genetically engineered males carefully selected for one thing only: breeding. They are hyper-virile beasts whose colossal muscles and endless stamina power their supermassive sexes into the wombs of the strongest, most fertile females of the Universe. This story follows the sexual exploits of one particular Seedmaker in his quest to unravel the mysteries behind his Creators... and his discovery of another equally fecund, equally powerful race of super females.
Caution: This Erotica Sex Story contains strong sexual content, including Ma/Fa Consensual Heterosexual Fiction Science Fiction DomSub MaleDom FemaleDom Rough Spanking Interracial White Male Hispanic Female Anal Sex Cream Pie Facial Lactation Spitting Squirting Tit-Fucking Big Breasts Size
The room was filled with hot, gurgling sounds as the belly inflated ... and inflated ... and inflated. Gooey, plucky noises followed. Something thick, bulky, and steamy was overflowing, coursing powerfully through some very narrow duct, being deposited hotly in an overstuffed, cramped receptacle, and then squirting out through the very few crevices that were available, dripping and falling hotly onto the ground, where it piled into thicker and wider pools of gunk.
The monster groaned while the female squirmed. Piercing pangs came from his back, his shoulders, and his sides, but the creature ignored them as the mere tickles that they were. “Uuurh!” If anything caused him any type of feeling, it was that coarse, thick cream that flowed so unendingly through his prick. “Uuurh-oooh...!!”
His grunts were low, heavy, and rumbling. With his breathing alone, the entire room shook.
“Ooo-AAAAH...!!!” On his hands, held up many feet above the ground, the female presented a completely different picture altogether: her every hair of her body was spiked, and her tail spasmed wildly, hitting the ground like a spear, as her cries and howls signaled pure pain and despair—the type of pain and despair that could only come—”OOOH-AAAH ... AAAH!!”—from experiencing the wildest, heaviest orgasms of her life.
Gunk! Gunk! Gunk! In the meantime, the male kept gushing. His pipe was crammed deep into the womb of the female. His seed flowed coarsely, so thickly through his duct that here and then the male experienced something of a discomfort. “Hmm ... mmrrrmm!!” With grunts and groans, he rotated the female around, moved her a bit to allow his breeder a little bit more breathing space.
To no avail. Always. Gunk! Gunk! Guunk!!” “Uuu-ooohhrr!!” With every female he encountered, the story was the same: too tight a sex, too massive a pipe. Squeeze!”
“AAAAHH!!”
The only good thing is that the females collapsed quickly, and he was allowed to plop out his breeding tool from their spasming sexes and then move on to the next female. “Uuurh...!” With the way he drove them to their climaxes, his breeding instrument spent more time outside a hot womb than inside.
“AAAHEEE...!!!”
The feeling of the cool air in his scalding rod was always soothing. That female, however, was taking a little longer than usual. Perhaps it was her feline genes that kept her struggling so much longer than most females of most species, and her stiff body and defiant countenance as she orgasm did betray some reluctance, some sort of pride that made her refuse, oh, simply refuse to collapse and fall asleep like all the others. “Uuurhh...!”
Like all the one hundred and sixty-seven others whose spasming bodies and swollen bellies littered that temple of breeding and procreation. “Oooorhh...!!” Still orgasming, the male did his duty. He couldn’t deny that the female’s resistance was valiant—even though her body was brimming with his seed; more of his alien seed inside of her than all the warriors and native males she’d ever bred it throughout her lifetime—times fifty!
Grinning and roaring, she took a defiant stance: “ਮੈਂ... ਨਹੀਂ... ਡਿੱਗਣ ਜਾ ਰਿਹਾ ਹਾਂ!”
The beast male only rolled his eyes. There was a time when he bothered to learn all those languages and translate all those specific little quirks from so many species.
Of all his “siblings”, he was regarded as something of an intellectual. A brainiac. A special, higher-quality stud who had more to offer than just perfect genes and the wildest orgasms any female could experience. He actually had some meat inside of his skull, a perfect complement for all the meat distributed so sexily along his seven and a half feet frame, and especially the massive meat he flaunted as a genital.
None of that, he discovered, ultimately mattered. He was a Seedmaker. He was a breeder from the heavens. His job was to make seed ... and with this seed breed all the wombs that were even remotely compatible with his flawless genes.
“Uuurhh!!” Feeling a thicker load course through his pipe, the male stretched one hand to the neck of that squirming female, then squeezed it. “All your womb will be pumping out are my offspring.” He spoke, even though he was sure she didn’t understand him. Not on the surface, that is. “I will never lay with you again. Ever.” He groaned. Another massive load of cream flowed through his pipe.
Gunk! Gunk! Gloorb!! The silhouette of the female’s belly, drawn so clearly against the tender lights and spotlights of that otherwise dark, moody room, rose and swelled with the thickness of his seed, and from the over-squeezed ring between her sex and the rim of his mega-pipe came squirting all the excess seed that no longer fit inside of her, dumping and falling loudly, hotly on the ground, where a pile of virile semen grew.
It wasn’t, by any stretch, the only pile of seed in the room. “Aaarh-AAAH!!!” Her body wasn’t the only one being tamed and subdued by the monster’s almighty sperm.
With her tail flailing and her cat ears spiking, the woman seemed to bounce back from full consciousness and half-consciousness, constantly tempted to fall asleep, but too stubborn to allow herself to fall, to kneel, to embrace defeat.
The monster choked her harder. Her paws came to his arm. They were huge hands of her own, with long and elegant fingers, five for each furry paw, and incredibly long nails that served her as weapons even when her body wore nothing, nothing!, and yet those nails—which he was informed were as hard as steel—barely made a prick on his skin.
“ਇੰਨਾ ਸ਼ਕਤੀਸ਼ਾਲੀ! ਇੰਨਾ ਰੱਬੀ!!” She came. Her body spasmed after she had grasped the man’s wrists and tried to defend herself—only to see that the full palms, both of them, could barely encircle half of the male’s wrist—which was easily the thinnest, less girthy part of his whole arm.
Her feline body thrashed wildly, and the orgasms came more uncontrollably through her throat: “ਤੁਸੀਂ ਇੱਕ ਬਦਨਾਮ ਦੇਵਤਾ ਹੋ! ਓਹ!! ਮੈਂ ਬਹੁਤ ਚੜ੍ਹ ਰਿਹਾ ਹਾਂ, ਬਹੁਤ ਕੁਝ!!!” She thrashed around, yet her body was kept firm above the air by the male’s grip—one hand taming her by the neck, the other lifting her on her back.
The gulping and slurping sounds of thick, hot seed flowing through a massive pipe kept coming. The belly of the female bulged out a little further, and it was clear that whatever resistance she still planned to offer was near its end: the female was shaking uncontrollably now, and her constant cries betrayed a consciousness on the edge of its resistance. With waves of orgasm flowing through her muscles, her abdomen relaxed and stopped offering the male any resistance.
GLUUUNK!! With one powerful load, the male inflated that stomach like a balloon. “Oooorrrh...!!” He rolled his eyes and finally experienced something of a pleasurable sensation throughout that whole orgasm. The stomach of his female, once so hard and unwieldy, now relaxed like it was turning to gel or liquid. Her belly, seen from the outside, looked gooey and wobbly, like tenderized flesh or the surface of a very thin balloon being filled with water.
Of course, the load that was inflating her and swelling her was much thicker than any water could be. The hot syrup kept gushing from her cunt, and the drips and drops of its thick, heavy pellets on the ground increased while the flow of semen also increased into her body, stuffing her womb with more semen than she would ever know what to do with.
“ਰੱਬਾ!! ਵਾਹਿਗੁਰੂ ਜੀ!! ਨਹੀਂ...!!” She screamed and thrashed around, all while the male sighed with the knowledge that she was only seconds away from the collapse.
“Congratulations.” With warm squeezes of his hand on her neck, the monster said somberly: “You’ve been the fifth or sixth strongest female in this offering.” He cast his gaze around, seeing swollen bodies everywhere. “Of all these females I inseminated, you’re the closest to being worthy of my seed.” Taking his other hand from her back, the male patted and fondled her swelling and growing belly fondling. “Your kind will be blessed with strong, virile children, and this offspring will grow up to rule your entire species, queens and kings and mighty warriors and sisters of battle whose power all flows from me.” Lowering that hand between his legs, he gave his mighty testicles a mighty squeeze. “A power that flows from my seed makers.”
The woman thrashed around as her beautiful eyes—yellow feline eyes that shimmered against that artistic darkness in the room—spasmed and rolled and hid themselves, almost, under her lids. “ਧੰਨਵਾਦ!” Throughout her thrashing and gasping, many exultations she gave to her man. “ਤੁਹਾਡੇ ਸ਼ਕਤੀਸ਼ਾਲੀ ਬੀਜ, ਸਟਾਲੀਅਨ ਲਈ ਧੰਨਵਾਦ!” Her body shivered, her tail wailed, and every hair on her furry frame was spiked like a razor, like thorns defending the most precious rose. “ਤੁਹਾਡੇ ਵੀਰ, ਸ਼ਕਤੀਸ਼ਾਲੀ ਬੱਚਿਆਂ ਲਈ ਤੁਹਾਡਾ ਧੰਨਵਾਦ!!”
The male sighed. His face had nothing but a “let’s get on with this” expression. “Who’s your daddy?”
He said those words as matter-of-factly and coldly as such words could ever be uttered. No difference: the female thrashed and spasmed on his hands like a whole power plant’s worth of electric currents were flowing through her, a mere conductor for enough electricity to power fifty of her planet’s cities: “ਤੁਸੀ ਹੋੋ!! ਤੁਸੀਂ ਮੇਰੇ ਡੈਡੀ ਹੋ, ਸਟੱਡ!!”
Shaking and screaming so wildly, the female’s defense instincts kicked up again: making full use of her paws and decently muscular, toned body—she was a warrior back in her land, you see—she tried tearing that man apart ... only to break several of her nails against his skin. “ਓਹ!! ਤੁਸੀਂ ਬਹੁਤ ਗਰਮ ਹੋ!! ਤੁਸੀਂ ਅਜਿਹੇ ਦੇਵਤਾ ਹੋ!! ਐਸਾ ਰੱਬ!!!”
The room was filled with the sound of needles of steel clicking and clanging on the ground—the nails that she had torn trying to pierce that god’s skin.
The monster huffed and puffed and moved his penis around, taking it a couple of inches back from her womb, then stuffing it back up and making her belly swell even bigger. «This will take her out for good.» He thought, putting his hand again on her back.
He didn’t need to hold her on the back like that. He didn’t need to hold her at all: with twelve inches of his breeding tool inserted to the fullest extent of what a woman’s sexual organs could take, the monster had enough cock inside of her to sustain her body and lift her up with the power and strength of his pipe alone.
If he held her like, so strong on her back and her neck, it was because he wanted to use her as a fucktoy; a living fleshlight with which he could give the tip of his cock some semblance of pleasure, and a fleshly hole that he could move around to cause enough orgasms on her to knock her out and relieve him from all his breeding duties for the day.
The female grew stiff as a rod. Despite her feline nature, her face was very much like his own—though female, of course: humanoid and not even that furry, and perhaps even more expressive than those species whose whole bodies were closer to his own physiology.
In that expressive, seductive face of a cat-like cock-devourer, he could read all the pleasure, all the devotion, all the love and undying loyalty he had forced upon her by the might of his cock.
She was now his, then and forever. Too sad he was never going to see her again. “No seed will ever conquer your womb.” He spoke. He wasn’t flaunting it either. “No male will ever displace the semen I’m ejaculating inside of you right now.” Once again, he rubbed her belly. Glunk! Glunk! Glunk! The overstuffed stomach was now hard. Her stretching was reaching its limits. About ten gallons of semen sloshed inside of her—eight gallons more than she could veritably take in any “normal” circumstance.
“My semen shall never leave you.” Moving that hand up, he pinched her nipples.
“AAARRHH!!!” The female shivered and shivered as her sad little tits began to lactate. She was a very lean and muscular cat lady, and her body did have that feminine curve, that waist-to-hip ratio that got his balls always so steamy and ready to pump...
... but her great musculature and leanness meant she didn’t have much of tits and ass to show, despite her wide hips. Combined that with her elegant, but altogether thin legs, and the male often thought he was fucking a very firm, very strong stick—and he had to be honest with himself: were not for his incredible willpower, his breeder would have never gotten hard for such a female. «Three Seedmakers failed to colonize her.» He reflected, counting the tremors of the female’s body with his hands. «I suppose they just didn’t find her too interesting.»
After the first couple of years of breeding, the Master had grown increasingly thin of nice breeding material for him. It seemed that the entire universe wasn’t big enough for his cock: with gush after gush after gush, he had seeded and colonized all the worthy wombs across the stars. All that was left to him and his brothers, apparently, was the B material. The middling beauties whom his seed was supposed to elevate—one generation at a time.
Sensing the absolute perdition of his woman, the monster leaned back and pumped his mega cock a couple more times into her womb. Another inch was crammed inside her sex, and the shape of her uterus was drawn very clearly on her furry belly. «Four eggs.» He saw the immense womb, which contained four ovaries instead of two. «I guess she’s breadable enough.»
The bulge clearly saw his seed flowing in four main streams, each stream battering one egg and leaving it no space to run. He smiled—a little surprise for that evening—and flexed his muscles involuntarily as he got another visual proof of his unparalleled breeding power: the semen, coarse and thick, was surrounding each ovary like a snake and crushing it, breeding every single egg they produced with so much power a slight hue of red glowed on that belly.
The woman was steaming hot, and his seed was the source of all this heat. “ਮੈਂ ਨਸਲ ਹਾਂ! ਮੈਂ ਨਸਲ ਹਾਂ!!” She gushed, eyes going wide and dry, drool oozing from her lips. “ਮੈਂ ਬਹੁਤ ਗਰਭਵਤੀ ਹਾਂ!!” She would have rubbed her belly proudly if she could move. Under the orgasms of her fertilizing stallion, however, all she could do was shake, shake, shake: shake and roar, shake and scream, shake and squeal, shake and peep.
Her cries became thin, then unhearable. Woomp! Her limbs went soft. Her legs, still crawling on the man’s back and hips, collapsed first, and then her arms followed.
Gluuursh!! Just as the female was beginning to collapse, the monster ejaculated another strong load inside of her. He didn’t quite have that much control over his ejaculations, and that bulkier load caught him off guard—but what for him was surprise, for her was terror.
“GOOORH...!!!” She made a gasping sound, then died out completely.
Bruuunk!!
Every inch of her body that could be hard and was indeed hard just one second ago—every muscle, every nerve, every tendon... —they all went limp in a blink, and one second later she was completely collapsed.
“Uuuuurhh!!” Groaning with a frustrated anxiety on his crotch, the monster removed her from his breeder. It wasn’t nearly as easy as a task as it sounded, given the extreme elasticity he forced into her sex or the excessive lubing his immense seed gave every inch of her vagina: his monstrous prick had way less than half its length inserted on her, to the fullest extent her physiology could take. “Uuuurh!!! Uuuurhh!!”
With all that supreme tightness, he felt like fucking the crevices of a mountain—though he had literally fucked holes into mountains during his training days, when the Masters were gauging his power and virility, and the feeling was altogether much more comfortable, much more loose and lax than that literal pussy of flesh and fur he was breeding to oblivion.
Real living creatures, when penetrated by a Seedmaker, tended to grow harder than the hardest materials known to all intelligent life in the universe. It was amazing, yes, this biological transformation a Seedmaker’s seed caused on their receptacles, indeed, but it was also agonizing: with his penis stuck inside such unwieldy vagina, the monster had to huff and puff to force the body out of his rod.
The only thing in that female that remained hard were her sexual organs. All of them. “Uuuuurh!!!” With a suction that would have torn bulls into mush, it was like her pussy was claiming his prick back, begging and screaming for him to never stop breeding it!
Inch after inch, the monster removed his seeder from that container. A massive jet of cum erupted messily and heavily from the oversized head of his monstrous dong once it was released. The let wasn’t long or strong; not the kind of shot that could cross a room and spray the walls like a hydrant; but the thing was bulky and heavy and filthy as fuck—a shot of painful restraint, like the male was doing his best to withhold it while the balls were working hard to pump it at its fullest power, and the result was a scalding bath of virile semen that covered the entire body of the female in two seconds.
Blooorsh!! Gluuurck!! Blooorshs!! In a single spurt, the semen spread out in all directions. Its net, almost a foot thick in its bulkiest, cast a shadow over the entire body of the female before falling—from toe to head, from shoulder to shoulder—and when it fell it was like a full bathtub of cum being dropped over her.
One second, she was clean and lean and muscular. The other second, she was one giant, limbless cum popsicle. Every inch of her had disappeared under a torrent of seed. No face, no limbs, not a single strand of fur could be seen.
“Uuuuurh!! Ooh ... uuuurhh!!!” Groaning low and hard, the monster squeezed his penis with one hand. Dropping the female on the ground and grasping her only by her ankles, the beast walked to a massive dry hollow nearby—a lower portion of the room shaped like a dry, circular pool.
Twenty-eight bodies, more or less, lay on that hollow already. Twenty-eight females of very different colors and sizes, but all shaped in that attractive humanoid form he enjoyed so much—the only physiology that a Seedmaker could reliably procreate with.
With only one difference: their humanoid frames, generally so voluptuous and curvy and sexy, were all now bloated and swollen with an excess of seed. The hollow also wasn’t entirely dry: before every gaping (and ever-spasming) pussy came huge and unending torrents of seed. The concentrated sperm swam inside the wombs and vaginas (and anuses and intestines and stomachs and throats of many as well) even hours after being ejaculated...
... and even after all this time the thing was as thick and juicy and virile as from the moment it first left the mighty balls that produced them; a powerful almighty broth that, as the stud himself professed, would forever remain in those wombs, no matter how much time passed or how many more dicks they all took into their crevices.
“Be gone, you ... cat!” Groaning with dissatisfaction, the monster cast the passed-out cat lady into the pile. Bloorsh!! Semen exploded from her pussy as she crashed on her side into the pile of equally passed-out ladies, then rolled down this pile onto the floor, where she settled. Semen came and came and came from her gaping pussy, its flow made a little easier by the profuse squirting she produced.
That species, he was told, wasn’t known for squirting or lactating—symptoms of their very problematic fertility, it was said—but that cat lady now was squirting and lactating quite a lot, which perhaps was a feat as great as making a rock cum or drawing milk from a metal rod.
Before the power of a Seedmaker, few things in the universe could remain chaste. Including dead, lifeless objects.
“Uuu-oaarh!!” Groaning low and deep, the monster squeezed his monster penis with both hands. His muscles glittered against the soothing lights of the dark room. His enormous knob shone in all its redness, steaming with the thick strands of ball juice that still squirted from its pisshole, no matter how harshly the male blocked the flow of his urethra.
Bulging and booming, feeling a growing throbbing pressure inside, the male jerked his massive monster cock with his ultra-big hands a couple of times, trying to bring himself to something close to “pleasure” after that whole tiresome experience.
“Bathe on my semen ... whores!” He grunted at them, though he really didn’t feel any power in those words. Releasing his cock, he crossed his hands under his mighty ass, and then he ejaculated.
Bloooorsh!!! The released stream of semen didn’t explode with anywhere near the power he remembered having in his youth, when he go to finally fuck his first real pussies. For his standards, in fact, it was something of a dribble: a bureaucratic and tiresome emission he had to perform every hour, if only to relieve his testicles from some mighty discomfort.
“Uuuurhh!! Uuuurhh!!!” Closing his eyes and trying to enjoy himself, the male felt the seed flow and bathe those luscious bodies in creamy white.
His ejaculation was a dribble—and still the first spurt covered the tip of the pyramid of women completely. The woman at the top, about five feet and a half in height and decently build, with big tits and nice ass, was completely flooded by messy cumload, and then the three, four ladies beneath her were covered by the downward-flowing semen as more and more loads were delivered over them—the arc of semen stretching about ten feet from the tip of the gushing penis to the very first body atop the pile; a very short stretch for that mighty male, and one that compensated for its lack of length with an abundance of width, froth, and bulk.
“Uuurh ... hmrmm...!! Hmrmmm...!!” The male squeezed his eyes and endured that delicious flow of power from his balls all the way through the thirty-or-so inches of his mega-breeding prick. As weak and rather mediocre as that ejaculation was—possibly one of the weakest in his whole life—the feeling of power and supremacy that came with any male ejaculation never ceased to please him; to make him feel, if only very little, a tingle of pride in his wide, godly-chiseled chest.
Five seconds later, half the pile of women was covered under his seed. Five inches thick, the layer of froth was, and it kept expanding and expanding as pump after pump after pump, groan after groan after groan, the male continue to relieve his balls from their excessive dump of cum. “Uuurhmm...!!” His baritone voice rumbled across the room. A hundred and seventy (or something) bodies trembled under its might—including those nearly thirty ladies he was bathing with his scalding semen.
“Hmrmmm ... rhmmmm...!!” Shutting his eyes, letting his masculine, chiseled face spasm a little, the male allowed a bit of a smile to dawn on his face—the first sincere smile he had in many a week. “Good ... feels good...!” Steam burst from his nostrils. His muscles hardened like an armor of pure power.
Ten seconds into the ejaculation, the main pile of bodies was completely covered by his seed, and the semen began to flow outwards and spread through the hollow, joining the other mounds of semen that were oozing from the few scattered pussies on that ground.
The hollow was about twenty-to-thirty feet in diameter, perfectly round, and some five feet in depth. The semen reached the cat lady, who was squirming harder than all others in virtue of being his last lay, and then surrounded her body whole, causing her to squirm harder and instinctively roll down with her face to the ground, fighting the pain that came from his overstuffed womb crushing against the floor, and begin to lap like a kitten on the virile froth, drinking as much from that semen as she could even while unconscious.
“ਇਸ ਲਈ... ਸ਼ਕਤੀਸ਼ਾਲੀ! ਅਜਿਹੇ... ਵਿਰਲੇ... ਵੀਰਜ!” She squealed as she drank from the life-giving, womb-conquering milk. Despite having been seeded and fertilized by that man from the very moment he had picked her up, lifted her off the ground, and penetrated her unceremoniously with his mega pipe, the lady hadn’t been kissed once nor taken his virile sperm anywhere but in her cunt.
Despite having experienced more orgasms with the mere touch of his hand on her shoulders ... hell, despite already cumming her heart out at the mere sight of that superb male specimen ... the lady yearned for a more thorough loving, and her experience with the mighty stallion, as mind-breakingly pleasurable as it had been, had still been only a ruthless, thoroughly utilitarian experiment.
She had been brought to be bred. To be fertilized.
He had been brought to breed. To fertilize.
So she was bred and fertilized by his mighty tool. No more, no less.
“Uuuurhhh!!” The male squirmed as his ejaculation began to petter out. He couldn’t remember the last time he was actually romantic with a female. As soon as he had reached prime breeding age, he tore through about two hundred and fifty females a day, every day for the first five years of his peak virility years, and even just one thousand bodies in (a mere trimester of breeding) he was already pretty desensitized for pussy, tits, or ass. “Hrmmm!!!”
After one hundred thousand females (little over his first year of breeding), he swore he couldn’t see a piece without vomiting. “Oh-hrmmm!!” It was mere sissiness on his part, of course, for he not only saw one more piece of ass, but he saw roughly eight hundred thousand of those. Even with his breeding pace somewhat decreased, fucking about one hundred and fifty to two hundred ladies a day, the mighty seeder had still collected another 450,000 bodies past his prime. Now, at the age of thirty, the ultra stallion was still fucking 150 new ladies on the regular, day in, day out, unrelentingly, and his score was fast approaching the respectable mark of one million wombs fertilized—a mark that firmly cemented his place as the top 5% of all Seedmakers.
Sensing gush after gush of sperm leaving his balls, the man opened his eyes and saw a giant cake of cream before him. Like pieces of meat flavored under the most delicious milk, the women were scattered and piled around two feet deep of semen—and rising. The pool kept growing and growing as the male ejaculated and ejaculated, his powerful semen barely reaching three feet beyond his mega cock-head, and a lot of its ooze flowing back to the mast and downwards towards the balls, smearing them whole.
Gluunk!! Glooorsh!! Gluuunk!! The giant testicles rose, then fell. Rose, then fell. Lifted, then collapsed, rising about a foot towards the iron buttocks and mighty thighs of the muscular stallion, then falling back a foot towards his knees as the voluminous broth of power had been released. The male sensed their every throb and their every gallon of seed flowing within their ducts. Even when seen from afar, those were the veiniest, most masculine balls any male could ever possess! Each testicle was the size of...
Well, to be frank, it was difficult to compare. From the moment he’d come out of the tube and began his lessons on virility and procreation, the male had seen very few things outside of his ruthlessly utilitarian purpose: the duty to breed! The obligation to spread his seed across every fertile womb in the universe.
As such, he had a very poor frame of reference when comparing his size or his virility to anything outside cold, abstract scientific measurements. The closest he could get to it was using the limbs and sizes of his partners: by this metric, for instance, a single one of his balls required three, perhaps four female hands to be completely encircled in their thickest ring. From top to bottom, their elliptical shape—the most perfect egg shape a male testicle could ever have—they measured about one whole palm spread out and a half.
Again, all these measurements came from the typical females he bred. Some blue moon here and there he would have a particularly big female, especially those coming from gigantic species (which were sadly quite rare), but most of the time (he would figure some 85% of breedings) the females would be from four to five-and-a-half feet tall. Regardless of boobs and ass, their frames were generally very short and puny, to the point he felt insecure before penetrating them even at the height of his thirty years of age—twelve of which spent in unrelenting, unstoppable, unfailing sessions of ferocious breeding.
The male contorted his face again, feeling the balls rise, then fall at a much lower pace. The semen never stopped flowing inside of them, but the relief from their most turgid states was always welcome. Uncrossing one hand from his back (while the other one remained relaxed over his super massive, round-but-hard-as-titanium buttocks), the male grabbed the mighty prick and lowered it down, making his semen ooze towards one edge of that circular rim.
At four feet of depth, his thousands of gallons of virile broth were close to overflowing the hollow. About fifty more of those hollows and pools were spread around the room—and each of them had been filled to the very brim; close to, but not quite ever overflowing.