Conquered By Motherhood

“Well, well!” chuckled Celestia. “Twilight Sparkle, behind schedule! I never thought I’d see the day.”

Luna - grinning just as widely as her sister - rested her chin on her interlaced fingers, and used her magic to levitate place settings over to Twilight’s seat. Teacup, saucer, teaspoon, and sugar bowl all set themselves down in perfect arrangement. “If your brilliant student is late,” said Luna, “It can only mean she was attending to matters of paramount importance. Please, Twilight Sparkle, take a seat and tell us what kept you.”

Twilight closed the tearoom’s door behind her, meeting the eyes of her two royal lovers. She was more accustomed than most to the presence of the royal sisters, but there was something freshly intimidating about the way they looked at her lately. Ever since they'd started formally dating a couple months back, the princesses’ love and admiration were undisguised - even when they were gently teasing her, as they were now. Being loved by the two most powerful ponies in Equestria was still overwhelming, and Twilight was never quite sure that she was enough mare for both of them.

But today she came with good news, and that fact buoyed her self-confidence. She took a seat between the two other princesses and got her thoughts in order, preparing to bring her lovers up to speed.

“Sorry to be late,” said Twilight, “but Doctor Cycle had an earlier appointment that ran long, and I didn't want to interrupt her…”

“Oh, Twilight,” said Celestia, using her magic to lift the teapot and fill Twilight’s cup, “you must get into the habit of throwing your royal weight around. You know - insisting that ponies drop everything for your sake, bellowing in the Royal Canterlot Voice when you don't get what you want… Luna, back me up here.”

“Oh, yes,” said Luna. “I can't recommend it highly enough.”

Twilight blushed, suppressing a grin. Her lovers really couldn't get enough of teasing her - and who could blame them, when she always gave them the reactions they were fishing for? “Even if I wanted to, er, assert royal privilege,” she said, “I was in disguise. We haven't discussed how public we want to make this yet.”

“Hm, sensible as always,” said Celestia. “So - what news?”

“The news is good!” said Twilight. “Doctor Cycle says my sperm are healthy, viable, and in all respects normal - aside from the fact that they come from magical testicles that don’t exist most of the time. I had her run every test you can, and the results were all good.”

“Well, there’s still one more test of your potency,” said Luna, running her hand along Twilight’s inner thigh, “and I’m looking forward to being a part of it.”

Luna’s overtly sexual gesture sent a shiver through Twilight’s body - and although she didn’t have a cock at the moment, she couldn’t help but imagine herself getting hard at the sight. As arousal spread through her body, she snapped into a different frame of mind - all of a sudden she wasn’t the anxious Twilight Sparkle who got teased by her immortal lovers. She was the dominant, big-dicked princess who fucked the royal sisters whenever she wished. “Can’t wait to be my broodmare?” she asked, licking her lips and gazing seductively at Princess Luna. “Oof, I could load up your belly with a big litter of foals, Luna…” She turned, eyeing up Celestia's midsection. “You too, Celestia… you'll be gorgeous when you're in the full bloom of motherhood, bearing all my little ones…”

Now it was Luna and Celestia’s turn to blush. Celestia took a deep breath - which made her chest rise alluringly - and steadied herself before responding. She could have stripped herself down then and there, begging to be fucked - but there were practical matters to think about.

“On the subject of, er, breeding,” said Celestia, “we should discuss precisely how many children we intend to have. Fantasies of growing immensely heavy with child are all well and good, but how many children do we actually intend on raising?”

Twilight’s mind, faced with a practical question, downshifted into analytical mode. “Well, we’re all busy mares,” she said, “and I don't expect that will change. Of course, some tasks can be delegated, and we can hire on nannies to help with child care.”

“Celestia and I have been discussing this matter between ourselves,” said Luna. “We believe the ideal number would be six; two children for each mother shouldn’t overtax us.”

“Especially if we space the pregnancies out over several years,” agreed Celestia. “If you were drooling over any hyper-potency enchantments, then I hate to be a wet blanket - but a conventional impregnation for each of us will be fine for now.”

Twilight let out a little snorting laugh. “I don’t know if I can do a ‘conventional’ impregnation,” she said. “Would you settle for a hard, passionate fucking that leaves you aching with pleasure?”

“That sounds like a very agreeable compromise,” said Celestia, demurely taking a sip of her tea.

“So we’re good to go, sperm-wise,” said Twilight, “but I've been researching pregnancy too! The data says that the most common cause of miscarriage and pregnancy complications is the embryo implanting in the uterine wall in an odd location.”

“My, this conversation took a rather sudden swerve in a much less sexy direction, didn't it?” said Luna. Celestia gave her a gently scolding look, and Luna waved it away. “Oh, I'm only teasing,” she said. “Go on, Twilight.”

“There's a spell in the medical literature,” said Twilight, “that a mother can cast during conception to guide the fertilized egg to an ideal position. The only problem is, it’s difficult to know exactly when the egg is released…”

“But there’s another spell,” said Twilight, “that permits the mother to control the release of her egg. Cast together, these two spells practically guarantee a successful pregnancy! They're rarely recommended, though; for one thing, it has to be the mother who casts them, which obviously rules out pegasi and earth ponies. And even for unicorn mothers, the second spell is particularly difficult - and casting it improperly would make complications a lot more likely.”

“I see,” said Luna. “Celestia and I should be able to cast both spells easily enough, after a bit of study… and then it's smooth sailing until we bear your foals.”

“Well, I can't guarantee ‘smooth sailing,’” said Twilight, “but I've done my best to remove every obstacle I can.” With a flash of magic, she manifested two rolled-up sheets of paper and set one down in front of each princess. “I’ve got the spells copied down here,” she said. “You’ll need to learn them both, of course, if you think this is a good idea.”

Celestia smiled warmly at Twilight, amusement tugging the corners of her mouth ever upwards. Of course her former student had covered every angle. How could she expect any less?

“It seems that you've thought of just about everything, Twilight Sparkle,” said Celestia. “But there's a single, solitary detail you overlooked.”

“Really?” said Twilight, tapping thoughtfully at her chin. “I really thought I’d considered everything…”

Luna raised a hand to her face, hiding a secretive smile. “Well, it’s not strictly required,” she said. “But there’s one step you usually take before getting a mare pregnant, if you wish to avoid scandal…”

Twilight took a moment to think, running through the process of impregnation from start to finish… but she couldn’t think of anything she’d overlooked. She met Luna’s eyes again, and noticed her hand in front of her mouth - its bare, splayed blue fingers…

Twilight gasped, her lavender body turning beet red. The air snapped as she teleported away - and Celestia and Luna only had a moment to share a giggle before she returned, holding a ring-sized box in each hand.

“Would you-” gasped Twilight, looking back and forth between the royal sisters. “Would, uh… both of you like to- would you be my-”

Celestia and Luna wanted to say “yes,” but they couldn’t stop themselves from laughing.

Any average pony who found their way into the realm of dreams would be likely to end up hopelessly lost, tumbling between minds, hurled out into the howling darkness each time they made a wrong turn. The setting of the moon would eject them - mercifully - and their heads would be swirling with senseless memories of impossible spaces.

But Nightmare Moon was quite at home in this space. It wasn’t just that she was powerful; she also had millennia of practice when it came to finding the easiest path between one dream and another.

Tonight, the traversal was simple indeed. Leaving Twilight’s dream and entering Celestia's was as easy as walking through a door; their minds were joined by love and years of bonding, which made their dreams cling together like two soap bubbles. Nightmare Moon pushed through the golden door to Celestia’s mind, and found herself inside a castle of pure white marble, red pillars, and golden trim.

This castle’s purpose was to exalt the mare known as Daybreaker, the fearsome ruler of Equestria. The only ruler of Equestria, in this dreamworld. Perhaps Nightmare Moon should have been offended that she had no place in Daybreaker’s perfect world - but that would be a little hypocritical, wouldn't it?

As the dark mare walked the halls of Daybreaker's castle, she couldn’t help but admire the regal portraits and immense golden statues she passed by. The first few depicted Daybreaker as a ruthless conqueror; there were paintings of her standing triumphant over ravaged battlefields, and ten-foot-tall statues depicting her holding aloft a flaming sword.

As Nightmare Moon drew closer to the throne room, she began to see more intimate depictions. Twilight Sparkle began to appear at Daybreaker’s side, clinging to the flaming mare or gazing adoringly at her brilliance. Notably, Twilight was was always depicted with a prominent bulge in her crotch; no matter what she was wearing, it clung to her stallionhood in such a way that her thick shaft and hefty scrotum were on proud display.

And by the time the throne room’s doors were in sight, the hallways had turned to a gallery of outright pornography. The paintings depicted Twilight penetrating Daybreaker in the bedroom, on the throne, on a hill overlooking a ravaged battlefield… And the golden statues presented Daybreaker with a colossally pregnant belly. She took obvious pride in the size of her baby bump, although it was an unconventional look for a conquering royal.

When Nightmare Moon reached the throne room’s doors, she swung them open and found Daybreaker on the throne - seemingly doing nothing in particular. “Hello, sister,” said Daybreaker. “I’ve been expecting you. I can always tell when you're planning something, even if it escapes Celestia's notice.”

“Oh, I would scarcely say I was planning anything,” said Nightmare Moon, feigning an air of modesty that suited her very poorly. “I thought I'd come by and congratulate you on your engagement to Twilight Sparkle.”

“The same to you,” said Daybreaker. “Although with everything that's been on Twilight’s mind, I worry that she doesn't even realize that she's engaged to us as well.” She smiled, and her mane rippled with a surge of heat. “We’ll need to remind her of that.”

“I’m sure she hasn't considered that you will be the mother of her children, alongside Celestia,” said Nightmare Moon, with a cruel little smirk. “Lucky for you. If she pictured you trying to look after a child, I think she would reconsider the whole arrangement.”

Daybreaker snorted. “You imagine that you are better suited to childrearing? I anticipate that Luna will keep you on a very short leash after the foals are born, lest they grow up to be as morose and jealous as Nightmare Moon. Even one child would grow bored of you very quickly, sister; it is the height of hubris to imagine you could keep six foals entertained.”

“And you think Twilight would entrust her goals to someone so self-absorbed?” spat Nightmare Moon. You'd barely notice if all six of them toddled off into a timberwolf’s den. I could manage a litter three times that size.”

“That boast rings rather hollow,” said Daybreaker, “since the princesses have agreed on six children, and no more. For all her talk of breeding and swollen bellies, Twilight is ultimately a very sensible mare.”

Nightmare Moon chuckled, and Daybreaker fixed her with a quizzical look. “Ah, sister,” said Nightmare Moon, “you think yourself to be Twilight's perfect match, but your knowledge of her heart ends in the waking world. I see her dreams, Daybreaker, and they provide me with delectable insights into her secret heart…”

“You've been spying on Twilight’s dreams?” asked Daybreaker. “Odd, I don't recall you asking for her permission.”

“Oh, come off it, sister,” said Nightmare Moon. “If you had the power to enter her dreams, would you bother asking her permission? And besides, I only did it tonight; I believe our engagement gives me implicit permission to know my beloved a little better.”

“I suppose,” sighed Daybreaker. “So your little jaunt gave you… insights?”

“They did indeed,” said Nightmare Moon. “Today, Twilight shared her research and made plans for a sensibly sized brood… but in her dreams she was promising to make Celestia and Luna into proper broodmares as she filled them with huge, gloriously potent loads. She dreamed of our bellies swelling up with foals at the very moment of conception… ooh, how we moaned with delight, struggling to lift our tremendously burdened bodies. That is what Twilight truly desires… and we have the power to give it to her.”

“You paint an appealing picture,” said Daybreaker. “So how do we help Twilight?”

“While Luna was studying the spells Twilight gave us,” said Nightmare Moon, “I studied them as well, paying particular attention to the ways that they could be… exploited. I determined that, with a bit of clever manipulation, the spells could be used to release and implant multiple eggs at once. We can secretly increase the number of foals, and become the gorgeous, gravid broodmares that Twilight desires.”

Daybreaker squirmed in her throne, rubbing her powerful, snow-white thighs together. “Oh, sister, I love it,” she said. “Even our counterparts won’t know what we’ve done until they are already large with child… and by then, they’ll be just as delighted as us to see their fantasies realized.”

“I quite agree,” said Nightmare Moon. “It is a tragic waste for mares as powerful as Celestia and Luna to deny their desires. They are living gods, striding over Equestria, and they should be bold enough to give themselves whatever they wish for. Especially when doing so would make their beloved Twilight so happy.”

“The royal sisters are fortunate to have us,” agreed Daybreaker. “Without us, they would be prisoners of their inhibitions, forever compromising their desires with that which they deem ‘sensible.’” She laughed confidently - but then her expression abruptly fell. “Sister,” she said, “I hate to bring this up, but… boastfulness aside, are we truly certain that we can care for great numbers of foals? The princesses seemed to take the question very seriously.”

Nightmare Moon scoffed. “I would not worry,” she said. “The princesses made an error when they settled on six foals for three mothers. They did not include us in their count, did they?”

“You make an excellent point,” said Daybreaker. “And of course the numbers should be adjusted for the two of us; with our unrestrained power, we can handle far more foals than Luna or Celestia alone.” She stood from her throne, her mane blazing and her head held high. “Very well, sister - when Celestia studies the spells Twilight provided, I will study them as well - and together, we shall become the big, heavy broodmares that Twilight Sparkle truly desires.”