You can never stop stacking the deck.

As it turned out, Isaac had to stand on the bed rather than kneel to get a good fucking angle on the much taller and bigger alicorn Princess. Yet even with how much larger of a woman she was, his cock still looked like it was too big for her pussy, the head alone looking like it would stretch her out enough to make her hips pop.

Isaac gently pushed his cock forward, towards the moment of truth. To his slight astonishment, Celestia's lower lips practically opened up on their own to embrace his tip, and from there it was a deliciously smooth entrance. Celestia moaned as his huge cock filled her up from below, spearing her to her core. Isaac couldn't see from his angle, but her abdomen bulged with the shape of his cock, too big to enter without magically stretching out the rest of her body. "Fuck, fuck, fuck...! Isaac, your cock is... It's perfect...!"

It probably wouldn't surprise anyone to learn that back home Isaac was little more than a well-read perverted virgin loser. Too shy and anxious to form strong social relationships outside the internet, and probably a little bit on the aromantic spectrum at that. So having a tall, powerful, magical, immortal Princess praising his cock the moment it filled her cunt was an experience that was so far out of his league as to be nearly incomprehensible.

But that was the whole point, right? To experience a life he would have never had otherwise. To make the world a paradise for himself for a change, rather than compromising on anyone else's rules and values. Even if there was years of societal training in his head telling him over and over again that he didn't "deserve" this, his middle fingers needed to be permanently raised to those voices!

Isaac kept pushing until he felt her ample ass smoosh against his crotch, his cock buried all the way to the hilt. He could feel her puffy pussy lips squeeze around his base along with the rest of her inner walls, caressing and milking his obscene length. "Ohhh, fuuuck...!"

"Mmgh, you like that, human...?" Celestia panted, rolling gently back and forth as she laid upon her own titanic tits. "You like the way my pony pussy pleases you~? It's all yours~. Fuck, I can feel you stretching out the entrance to my womb...!"

Isaac's heart raced, his masculine instincts overwhelmed by primal stimulation. He took a deep inhale through his nostrils, drinking deep of the mixed scent of lust in the air, and started thrusting his hips back and forth. His ridiculously enhanced cock slid out and into Celestia's soft, wet, stretchy, **** pussy with remarkable ease, while she made sure to squeeze him with her inner walls and give him the friction and tightness he needed.

It was all deeply arousing and stimulating, but a part of Isaac still wanted more. He wanted to utterly claim her, to take her, to prove to the world that he owned her. The tingling of his full balls bouncing between his legs gave him inspiration. "Mmrrrgh... Am I about to bloat you up... with so much cum... that you'll look pregnant?"

Isaac's balls suddenly felt much heavier, swollen with more sperm than he could imagine, the skin of his sack full and taut with their virile contents. His cock tingled as it felt like the inner channel of his urethra had widened slightly, the muscles within all preparing to pump an insane amount of seed...

"Yes, yes, YES!" Celestia squealed, not acknowledging how reality had changed once again. In fact, it looked like there was more leftover cum on her face and the bed than before, from Isaac's previous orgasm retroactively increased. "Flood me, Isaac! Fill my pussy to bursting with your wonderful cuuum!!"

Well, who was he to deny a lady's fervent request? Isaac grunted and then saw white for a minute, as his cock became so overloaded with sensation that his other faculties took a back seat while his dick lurched and pumped an obscene amount of semen deep into Celestia's womb. Each pulse felt like a river channeling through his loins, his balls and other internal glands working like industrial factories to deliver an absolutely insane amount of cum. Human beings weren't meant to even NEED to make this much cum in any given situation, but in the pursuit of an unrealistic lustful fantasy, Isaac had turned himself into the evolutionary equivalent of a population explosion.

And Celestia was taking all of it. She grunted as with each pulse slamming into her womb and splattering inside her body, her belly slowly began to fill up, pushing down against her cushions of breast. She eventually had to lean forward and lift her ass a bit, giving her stomach room to droop down behind her breasts as it grew more rounded out with Isaac's womb-bloating cum. And that was just the cum that settled inside her, as even more of it sprayed out between her cunt and his cock, dripping down and staining the red velvet mattress further.

Ultimately, Isaac wasn't sure how long it all lasted. All he knew was that eventually the convulsions rocking his body finally faded, and it was all he could do to fall back onto the bed, his cock slipping out of the alicorn's pussy. He was still hard, but the rest of his body was winded from the sheer intensity of that orgasm, and even more cum oozed from his cock from how full his balls still were. Celestia, meanwhile, looked just as winded, panting as she laid on her breasts and stuffed womb, the mother of all creampies oozing out of her pussy whenever she didn't have the strength to clench her pussy lips shut.

_So this is what it's like to be a hyper furry porn character... _Isaac thought to himself in the grand post-nut clarity that followed as he stared up at the ceiling.

Celestia whimpered and shuddered, more cum spilling out of her cunt and running down her plush thighs. "I... came... so much..." she cooed, panting for breath. She shifted on her breasts, laying one cheek down on her left breast so that she could look back at him. "Isaac... I've had dildos, I've had magical temporary cocks, I've had grateful males overcoming their **** to give me a night of passion... But I've never felt so... so satisfied so quickly. You were right - you being a true male makes all the difference...! Oh, I'm so glad...!" She actually looked like she had tears of joy about to emerge from her big magenta eyes. "My little ponies are finally going to have a Master...!"

Isaac sat up and looked around the thoroughly ruined bed. He realized after a moment that he wasn't a big fan of being messy, in retrospect. Bloating up ponies like living condoms were one thing, having to potentially navigate a swamp of his own muck was quite another. "It's a good thing at this point that you've mastered easy, thorough, 100% effective cleaning magic rituals that anyone can use, right?"

"Oh, of course," Celestia replied casually, not bothering to lift a finger to clean up all the cum oozing across her body just yet, "but that means we have time to just... feel the results for a while. Mmm..."

Fair point. If they could snap their fingers and get instantly clean after a particularly juicy fuck, that just meant there was a niche for being covered in cum for a while... which Celestia apparently had. Isaac dropped that line of questioning and followed one that had just come up. "So... what did you mean by your ponies finally having a Master?" Phew, thankfully a non-basic question.

"Didn't I tell you? That will be then. Put aside your worries and focus on now..." Celestia replied, clearly both too tired and not willing to change subjects just yet. Though she gave him a playful smirk over her shoulder. "Unless you're already getting tired of me and want to move on to another mare, hmhm~."

Isaac grinned sheepishly, feeling a little caught. "Would you creatures find that hot if I did just wanna change partners frequently?" he asked strategically. Variety was the spice of life, after all, and he didn't see himself changing that aspect of his lustful behavior anytime soon. The key was making sure that none of the girls (or guys) he chose to fuck were offended by being left hanging.

Celestia's shoulders shivered as she was overcome with a surge of lust. "Ohhh, my virile and manly Master...!" she crooned. "I'd absolutely call some more servants in here... if I wasn't craving you in my other holes, hmhm. Why do you think I cleared all my appointments for the rest of the day? I wanted to break the ice, break you in, make my case for being your First Concubine...!"

Isaac had no idea about the significance of the 'First Concubine' at this point; he just found it hot to have this powerful, immortal demigoddess pining after him. Though her comment about filling her other holes gave him a little pause. He didn't want every creature he fucked to become a checklist of tits-mouth-pussy-ass over and over and over. He thought for a few moments about how he wanted to address that, and came to a quick decision. "Isn't it true, though, that when it comes to the harem master, there's no sense of obligation or reciprocity, because you're all so organically hard-wired for submission that just knowing that your master is enjoying himself is enough to make you feel more than fully satisfied?"

"So you have been reading up on herd dynamics..." Celestia mused. Her horn flared with golden light, sending a wave of magic over herself and the bed. All the cum and pussy juices left over and staining the bed instantly evaporated, leaving only what was freshly oozing from Isaac's cock-tip and rounding out Celestia's belly. She slowly turned over and rolled back into a sitting position, her breasts settling on either side of her sloshing stomach. "But you may have missed some context. That's not just for any male that makes us cum - forming a harem and becoming a master are very socially and culturally significant processes that unlock our full sense of submission." She let out a little sigh. "Otherwise... yes, we probably would have been conquered by tyrants long ago as we gave into our urges to serve. I've been so worried that we'd fall for the wrong male, so I've defended my sweet ponies for over a thousand years..."

Well, that was an interesting answer. Even though his answer was still ultimately 'yes,' it seemed some nuance to it got thrown in. Maybe because otherwise it would have drastically altered the timeline due to some past event, maybe even resulting in this conversation not even happening... That was a little chilling to think about. Though that didn't stop him from thinking of more potentially drastic reality-altering questions. "I know I'm asking a lot of questions about this world and creatures in general. But you don't mind, do you?"

"It's perfectly understandable in your situation, Isaac," Celestia reassured him with a smile. "And you know what? It's really cute - my nerdy little would-be-stud getting curious about our world and its peoples... I think that's a good quality to have in a master, if you ask me!" She looked hungrily at his still mostly erect cock and licked her lips. "Though perhaps you won't mind if I... have a little treat as a reward for answering your questions?"

Isaac blushed at her forwardness, and his cock twitched, still needy for stimulation. "A-Absolutely...!"

"Perfect." Celestia's horn lit up again, and Isaac found himself gently pushed back until he was laying against one of the massive cushions of the throne-bed, as Celestia hauled her cum-swollen body between his legs. Her breasts smothered everything below the knees as she laid on her front, leaning down and staring at his girthy cockhead. "So, Isaac, what's your next question?" she asked invitingly, before dipping her head down and taking the first few inches of his cock into her equine muzzle.

Even though he'd already had an incredible titfuck and fucked her impossible pussy, her worshipful, hungry mouth was yet another wonderful experience Isaac wasn't ready for. "Ah- Mm- Well... Do all alicorns have oral fixations?"

Celestia just looked up at him mid-suck and winked, not removing herself from his cock for even a second. Her head bobbed down, a little hungrier, sucking him deeply like she was trying to really savor his flavor.

Isaac swallowed dryly, his concentration broken for a few moments. What had he been curious about, again? Oh, yeah, there was a problem hanging overhead to solve, one that was a little awkward and would maybe require some drastic question-asking. "Is it true that every sapient creature in this world is 18 years old or older? Is there no other sapient creature around below the age of 18?"

Nothing changed about the situation or his surroundings, but Isaac almost felt the world jump a tiny bit, as if the planet's very mass had shifted. Celestia popped her lips off his cock, slurping up the string of saliva bridging her lips and his tip before answering. "Mmm... I'm sure that must have given you some pause, seeing only adults around."

So it had worked?? He hadn't even specified a method or an explanation in those questions, so... the world must have come up with one, hadn't it? "How is that... possible?" And once again, he immediately stumbled into a question that was thankfully not Yes or No.

"If you're not familiar with pocket dimensions, alternate universes, temporal manipulation, and rearing foals, it's a very complicated explanation," Celestia replied thoughtfully, running a hand through her long, wavy auroral mane. "Suffice to say... Many, many years back, our resident chaos goddess, Eris, decided that she wanted this world to be a sexually free haven, so she connected our world to a mirror world that loves raising the young as much as we love sexual submission. Our newly born go there to be raised and educated, along with the parents to take care of them. 18 days later in this world, they return - the foal a fresh adult, and their parents having barely aged at all." She sighed. "It was a rocky transition, working out the details, but the convenience of it all won over the peoples of the world. And even then, it's a reckless and imperfect plan. With new creatures entering our world ready to breed almost instantly, we're going to be facing a population crisis within the century..."

Isaac wasn't expecting such an... out-there answer. But if it solved the problem of having to pump the brakes on the sexy times, whatever worked, worked! Mostly. "Er... Birth rates are pretty low in this world anyway, right, on top of the males being **** to breed?"

"Another evolutionary reason for having sex so frequently," Celestia admitted, her face lightening up. "Thankfully we're not being inundated with brand-new young mares and stallions, so it will be sustainable for some time to come." With a pout, she added, "I'm still annoyed with her for tearing and re-stitching the borders between realities so casually, though." Then she took his cock back into her mouth, and she seemed to calm down some more, enjoying the simple pleasure of having his hot, thick cock against her tongue.

Isaac swallowed. Yeah, imagine casually rewriting reality...

Celestia's hungry mouth distracted him for another minute or so, before he could think of his next question. ...But he was running out of bases to cover, boxes to check. The world was pretty close to being his ideal ripe playground. And while he was looking forward to asking questions that affected individuals down the line, in terms of the big world-changing stuff he felt like he was close to the mark.

Then again... "So the, uh, 'official' process for becoming a creature's master and forming a harem... It involves applying some kind of magical symbol on the submissive's body, kind of like your Cutie Marks, in the form of a brand or tattoo, right?"

Celestia hummed around his cock, almost chuckling. She lifted her head once more and fixed him with a sultry, smug expression. "Looks like someone was doing some real thorough research long before he came here... Though I should tell you it's all theoretical - no one's experienced a successful, true Branding in thousands of years. But that doesn't stop us from fantasizing about it, preparing our whole lives for it." She leaned down and gave his tip another lick with her long tongue. "But again, you're thinking too far ahead. That time will come, and I'll make sure you're ready for it. For now... maybe just think about what you want your Master Mark to be~..."

The flow of questions stopped there for a while, as enjoying Celestia's worshipful blowjob became more important than inventing hypotheticals about the world that would become truth.