Big Mare, Bigger Family

“Alright, you two.” Twilight double checked the trio of folders in her magic. “You've passed all the preliminary tests and gotten all the clearance, so we're ready to do this. Are you positive you want to go through with it?”

Scootaloo, well over nine feet tall, looked down at the smaller Twilight. She had a familiar cocky smirk more usually seen on a certain other brash pegasus. “You know we are! Isn't that right, Rumble?”

Rumble sidled closer to Scootaloo, leaning into her strong chest. Even at seven feet tall, his head barely came up to her withers. He shivered as he inhaled deep, catching a whiff of the heated scent emanating from her nethers. “Heh... Let’s do this.”

Twilight shrugged. “Okay, then...”

She led Scootaloo and Rumble into one of the castle bedrooms. A complex magical array had been drawn on the floor, crushed gemstones gracing the lines to make them glitter and shine with eddies of magic. Scootaloo had to crouch to squeeze into the smaller room, her broad shoulders scraping the frame of the door. It soon became apparent that she took up a quarter of the available space by herself! And if that weren't enough, Rumble followed right behind, who also needed to duck his head!

Between the two giants, there wasn't much room left for Twilight.

“Right...” Twilight shuffled past to stand by the window. “There are varying levels of power for fertility spells, level one being the weakest, level five being the strongest.” She gestured to an ancient-looking book on the table. “Normally I'd suggest a level one and see what kind of results that yields. But seeing as I'm aware of your intent here—”

Scootaloo and Rumble waggled their eyebrows.

Twilight blushed. “I-I'm willing to step it up a little. A level three fertility spell cast on a healthy couple will likely do the trick, and with this particular iteration, I can do both of you at the same time! Scootaloo, the Proportion spell that's now permanently a part of you is obviously still in effect, so regardless of how pregnant you get from this, there shouldn’t be an issue. You can expect that the symptoms of your estrus will be amplified, though, so be ready for that a few minutes after the spell is completed.”

Scootaloo bit her lip. It already felt like her nethers were on fire, and she'd been horny all freaking week! Being this close to Rumble yet unable to fuck was torture. “Then you better be ready to leave right away, or else you're gonna get a front row seat of Rumble rutting my brains out.”

Twilight snickered. “Don’t worry, I was planning on leaving. Rumble, there’ll be some growth in your genitalia, particularly in your testes and scrotum. But as requested, I've also tied in an additional spell to increase the overall size of your penis. You'll need to see me later if you'd like it to be permanent. You'll also feel a tingling sensation farther back from your prostate being enhanced, and like Scootaloo, your libido will be put into overdrive soon after the spell completes. Understand?”

Rumble fidgeted. Their three bodies were quickly warming up the room, and the combined space was just making the smell of Scootaloo all the more potent. He was hard as a freaking rock, and if this kept up, Scootaloo wasn't going to be the only one dripping “Got it.”

“Good.” Twilight checked the tome one last time. “So a level three, then... I think I've got everything right. It's actually kind of interesting—this array is identical for levels three and four of the spell; it's just the incantation and power expenditure that are different! That's usually not the case in spells like this...”

“So can you cast a level four instead?” Scootaloo gave her puppy dog eyes. “Pleeeeeease?”

Twilight rolled her eyes. “Be happy with what you're getting, missy. And just so you know? That trick doesn't work as well when you're near twice my size.”

Scootaloo kicked at the floor. “Aww...”

Twilight read over the instructions one last time. “Okay, here goes. Stand still, you two.”

The buzz of magic filled the room. Scootaloo felt herself being engulfed in the electric sensation of Twilight's magic focusing deep within her. Rumble felt much the same as well, making them both twitch and squirm. The lines of the array started to glow, purple, then blue, then white. Twilight chanted out a string of words under her breath as the light around her horn grew brighter, then brighter still.

The heat in Scootaloo's loins became muted, the burning feeling almost ticklish, her insides emitting a soft gurgle. A fog lifted from her eyes as the haze of estrus cleared, endorphins and chemicals undergoing a soft reset. She heard Rumble moan beside her, and while she couldn't very well see, she could picture his hefty nuts swelling to greater sizes, his cock growing to the point it could fill her once more. She drooled at the thought of deepthroating him being a challenge again, not to mention the bliss of his thick, virile girth spreading her wide, pumping out untold amounts of cum into her waiting womb...

“There!” Twilight wiped off her brow. “All done!”

Scootaloo blinked. She hadn't even realized she'd zoned out. “Wait, really? That's it?”

“Yep!” Twilight said. “The spell doesn't require a lot of power, it's just rather intricate. Nothing I'm not used to. How do you guys—”

Zrrrrm! Zrrrrm! Zrrrrm!

Twilight jumped. She looked back at her flank to see that her cutie mark was glowing, flashing on and off again.

“Oooooh! A friendship problem!” Twilight clapped her hooves. “What good timing! I'll just leave you guys to uh... Do your part, and you can let me know how everything goes! Best of luck on everything! Give your boys hugs for me! Byeeeee!”

She teleported away with a FLASH!

Scootaloo and Rumble were suddenly alone in the cramped room, staring at each other with blank eyes.

“Just like that, eh?” said Rumble.

Scootaloo shrugged. “Guess so. You feel different at all?”

Rumble shifted his hips. “Definitely a little heavier back there. You?”

Scootaloo shook her head. “She did say it'd take a bit to kick in. Maybe we should wait?”

Rumble considered that. “I suppose—”

Suddenly, the door opened.

“Hello? Guys?” Starlight walked into the room, craning her head up at Scootaloo and Rumble. “Holy... I forget how big you are now... E-Erm, I just saw Twilight teleport into the meeting room with her cutie mark glowing. She didn't have to leave before she could cast the spell on you, didn't she?”

Rumble frowned. “Actually, she—”

“Yes!” Scootaloo cut in. “She was just about to cast it and everything, but then her cutie mark started buzzing and she had to go. It stinks! We were all ready to go here, too...”

Rumble quickly mirrored Scootaloo's somber tone. “Man, I really wish she didn't have to go like that! Oh well, I suppose that's what happens when you're a princess...”

Starlight chewed on her lip. She looked at the array on the floor, then over to the book on the table. “Well, if you want, Twilight's had that book for a week now, and I've taken a look at it in my spare time. If you're comfortable with it, I could probably cast the spell in her place.”

Scootaloo perked up. “Hey, yeah! You could do it, couldn't you? I mean, you did so well with my Proportion spell, why wouldn't we be comfortable with you?”

“You'd really do it for us?” Rumble said with wide eyes. “You don't mind?”

Starlight smiled. “Of course I don't mind! I know how much you've both been wanting this, and I've seen you enough with your boys to know you're great parents! I heard Twilight say that you've got all the paperwork done, so I don't see any harm in stepping in for her. How hard can it be?”

Starlight floated over the spell tome and flipped through it. But while she was looking, both Rumble and Scootaloo felt a familiar pressuresneak up on them, followed by an gathering, coiling ache. They started to fidget in place, sweat forming on their brows as they tried to play it cool.

“Let's see...” Starlight repeated a few phrases to herself. “So this array is for levels three and four of the spell? Wow, that's usually not the case in spells like this! Did Twilight say what level she was going to be casting?”

Scootaloo licked her lips. “Four.”

Starlight glanced up at her. “Wow, you talked her into a four? Are you sure? The fertility rate and compatibility of you two is already above average. A four stands a very high chance of a higher case of multiples, and if it's any more than quadruplets, the Proportion spell's going to activate in you! You'll wind up being even bigger than you already are! Permanently!”

Scootaloo felt herself wink, hard. The scent of her heat intensified, the horny haze re-blanketing her mind. “It’ll be fine, Starlight. Trust me.”

Starlight bit her lip. This towering, massive, motherly mare before her, looking down at her with a kind smile... She didn't quite understand why, but the thought of amplifying all of Scootaloo's maternal traits, to see her even more than she was now...

Starlight looked to Rumble. Mischief twinkled in his eyes, his lopsided grin almost making her laugh. His huge, raging boner was almost eye level with her, sticking well out past his chest and thicker around than one of his legs. She could see his balls, too, heavy and massively fat with seed, so large that he was almost bowlegged. He must've already had some enhancements to better please his enormous wife.

Starlight laughed. “Okay, okay! If that's what Twilight agreed to, I'm not gonna make you convince me. Four it is, then... Oh! Rumble, I heard Twilight say she was gonna add in a male enhancement spell for you, so I can do that, as well. Did she also tell both you about what to expect from this spell immediately afterwards?”

Scootaloo was finding it harder and harder to keep a straight face. Every instinct in her body was screaming at her, to take her willing, horny mate. And judging by how Rumble was now shaking, he likely felt much the same. “Y-Yeah, she did...”

“Alrighty then!” Starlight widened her stance. “I’ll need you guys to hold really still for me, okay? The effects of this spell are permanent, and even on a failed attempt, the effects are cumulative with every completed casting. If I did, say, a level three, then cast a level four, the effects of both would build off each other once I’d successfully cast the four! Then you'd both be really, REALLY fertile, heh...”

Scootaloo and Rumble didn't even have time to reply to that, for the buzz of magic had returned. Starlight's magic felt crackly rather than electric, but it did much the same, encapsulating them before focusing in on their groins. They both had a moment's reprieve as their hormones and urges were 'restarted'.

Rumble looked down this time to watch his penis grow. Little by little, his head and shaft swelled more and more, inflating with each new beat of his enhanced heart. He felt his balls sink lower, hanging below his knees and then some, his sack burgeoning as his nuts sloshed and churned with so much cum... Meanwhile, Scootaloo's eyes were unfocused, her thoughts completely turned inward to the tingly sensations within, so hot that they felt cold...

“Ha! That wasn't so bad.” Starlight closed the ancient spellbook and beamed. “All done, guys! How do you f—”

She was cut off by Scootaloo and Rumble tackling each other. There was a loud SMACK as their humongous bodies collided, kissing and fondling and groping. In a surprise move, Rumble spun around to let Scootaloo's weight carry her forward, landing with a THUD that shook the room. He rolled her onto her back and stepped over her, his mammoth dick dripping and twitching.

“E-Erm...” A fiery blush formed on Starlight's face. “I'll just, u-um... Yeah...” She teleported away with a FLASH!

Rumble had to move at an odd angle to line himself up, but before long he THRUST inside Scootaloo, making her SCREAM long and loud. He stuffed inside her cunny without any gentleness, a feral creature of lust and need. Scootaloo squeezed his colossal pole with all her titanic strength, sucking him deeper and deeper inside, his head already bumped against her cervix like she was still a scrawny shrimp. He nipped and licked her chest like a stallion possessed, hammering her with all his mighty strength, molding her velvety tunnel with each thrust. Her huge wings flared out with such strength that they snapped crystals off the walls, creating long divots as she brought them forward to envelop her stallion.

“RUMBLE!” Scootaloo's scratchy voice cracked. “Y-YES! MORE! MORE! MORE!”

Rumble fucked her hard and fast. He saw nothing but her, heard nothing but her, felt nothing but her. His entire world was Scootaloo. He buried his muzzle in her orange fur and kept pistoning, the only thing registering was when his engorged cock became fully hilted. But even then he didn't form a proper rhythm, merely obeying the snarling, slavering beast inside him, growing more and more insistent as the second fertility spell kicked in. He hooked his hooves around her shoulders and pushed EXTRA hard to for those last precious centimeters, and he relished the needy howl that ripped free of her, his gurgling balls slapping against her extra-large rear.

There was no warning for when Rumble came. One moment he was thrusting wild and savage like an animal, and the next he'd erupted inside her, filling her cavernous depths with thick, hyperfertile seed. Scootaloo's voice reached a new volume with his climax, and not a pony within a hoofball field's radius didn't hear. He filled her over and over and over, his beach ball-sized balls pumping her full to the brim, her belly soon swelling with his virile gift. She wrapped her legs around him and clamped down hard as she could, feeling his thick, wet heat pooling inside her, then ballooning inside her...

The orgasm itself lasted less than a moment, but Rumble didn’t stop. Within seconds he was thrusting again, just as hard, just as fast, his balls fuller than ever. Scootaloo's eyes rolled back into her head as wave after wave of pleasure washed over her, but yet she still hungered for more, more of Rumble's seed... More of his beautiful foals...

“Whew…” Scootaloo panted for breath. “I think that’s the longest we’ve ever been at it…”

Rumble nodded. He laid sprawled atop her, one of her enormous wings over him like a blanket. They’d fucked each other silly for they didn’t even know how long, with no care to stop or censor themselves.

“You’re telling me... Holy fuck...” He could barely feel anything south of his stomach, yet an impulse still pushed him to move his hips, gliding in and out of Scootaloo’s flower. “Magic, huh?”

Scootaloo had to agree. It was a few more minutes before they disengaged and got to their hooves, but they managed, their urges now a dull roar.

Upon getting up, Scootaloo became aware of a faint buzzing. She blinked and swivelled her ears all around. “D’you hear that?”

“Hmm?” Rumble flicked his ears, as well. A strange low hum faded in, droning in the air around them. “What IS that?”

They both glanced up. A semi-transparent blue dome stretched above them, or in the case of Scootaloo, only a few inches over her head.

Rumble couldn’t help but snicker. “I guess I was loud.”

“You mean I was loud.” Scootaloo grinned and helped her husband off the floor with one solid pull. “Being bigger means I got louder, and I was already a screamer.”

The two oversized pegasi took a few minutes to catch a breather, preening each other’s wings back in order from their frenzied lovemaking. They left the loose feathers in a pile for Twilight to use as quills. It seemed only right for the hassle.

“They won’t make Spike clean this, will they?” Scootaloo’s gaze drifted down to the sticky puddle of sexual fluids pooled and smeared on the floor.

Rumble shook his head. “Nah. I’m sure one of them will just zap it away. Why wouldn’t they with their powers? I mean, come on! Look what they did to us!”

Scootaloo felt her pussy spasm. She wouldn’t mind having them do this a few more times, to be honest. “Speaking of what they did to us, do you feel any different? I mean, I suppose it’s way too early, but part of me expected something to happen as soon as we’d…”

Rumble patted her shoulder. “I wouldn’t think too much on it. The Proportion spell didn’t work immediately, remember?”

“The Proportion spell was only cast once, and only AFTER I was pregnant.” Scootaloo’s wings flared out, smooshing against the dome so much that her tips flattened against the floor. “A greater chance of pregnancy isn’t a guarantee, babe. What if we need to keep having sex for this to take?”

Rumble was too distracted to reply by the absurdity of her wings. He started laughing, and Scootaloo noticed and soon followed, two huge ponies in a tiny fuck dome.

“Well, I think I can safely say walking is going to be impossible.” Rumble shifted on his hooves, his engorged junk swaying like a sack of grapefruits between his legs. “Sorry hun, but I don’t think this can be permanent.”

“Awww…” Scootaloo sat on her haunches and pouted. “You know, it wouldn’t be such a problem if we convinced Twilight or Starlight to let you join me up here in the clouds. Part of me misses you being the big boy on campus. The way that you took me just now, claimed me as your mare… that was hot as fuck.”

Rumble stepped forward, nuzzling Scootaloo’s warm chest. “Nah. We both know you like being the bigger pony—”

BANG! Scootaloo’s entire body spasmed, shooting rapidly up in height.

“OW!” Scootaloo’s head bashed against the forcefield. She stooped down in a slouch, but even that had her pressing against the ceiling. “The HAY?!”

Rumble did a double take. “Did... you just get bigger?!”

“What?!” Scootaloo tried to readjust herself, but even with her legs spread, the top of her head ressed against the magical dome. Just five seconds ago she’d had a few inches clearance! “How?!”

“I… don’t know. But you’re bigger. Again!” True enough, where before Rumble had been eye level with the top of Scootaloo’s chest, he was now staring directly at the bottom.

And she wasn’t even standing straight!

The shield spell fizzled before either could respond, and there was a knock on the door. Starlight walked in with a dull expression on her face, her horn flashing immediately upon her entry. The rank smell of sex vanished in an instant.

“I was wondering when you’d stop screwing long enough to notice that I’d put up a sound shield.” Starlight looked between them. “You’ve been in here over an hour already. Get it out of your systems yet?”

Scootaloo stood up to her full height. Starlight’s eyes shrunk to pinpricks as she registered the change, gasping as she realized she only came up to Scootaloo’s knees!

“Uhhh…”

Rumble gestured to Scootaloo. “Know what might’ve caused this?”

It was almost comical. Side by side, Rumble and Scootaloo looked more like mother and son than husband and wife. Rumble’s head was now level with the space below Scootaloo’s chest, meaning he could almost walk underneath her without ducking! Him! Rumble! The supersized stallion that towered over everyone else in Ponyville!

“So, uh...” said Starlight. “When I established the Permanency spell, I made it so the Proportion spell would ‘flicker’ in the event of a new pregnancy. You know, basically a test to make sure it was working in case it was needed. I, erm… suppose I should’ve told you earlier, but having it activate like this means conception has occurred! You’re officially pregnant again! Yay!”

Scootaloo’s eyes went huge, adopting a open-mouthed smile.

“Ha-HA!” Rumble pumped his hoof. He fluttered up to give Scootaloo a kiss, holding his head in her hooves. Scootaloo moaned and melted into his touch, pulling him into a soft embrace as they—

“A-HEM!” Starlight stamped her hoof. “You both must be tired after all that… erm, activity. I’d be happy to teleport you guys home if you’d like! Maybe you could continue your celebrations there?”

Scootaloo and Rumble parted, laughing. “Nah, I think we’re good,” said Scootaloo. “After being cramped in this tiny room, I could stand to stretch my wings. You with me, babe?”

Rumble snickered. “This room IS a little small. Some flying sounds good.”

Starlight bother didn’t comment on how this was one of the largest suites in the castle. With a flash of her horn she cleaned up the mess on the floor, then showed the two lovebirds out with a wave and a smile.

“Good luck, guys!” She closed the castle doors with a SLAM!

“So then, Shorty.” Scootaloo took lead, trotting a ways down the path. “You really wanna fly back? Or would rather walk so you can appreciate the view? Might be hard with those bowling balls between your legs, though… you might have to flutter behind me like a breezie.”

Rumble grinned. Scootaloo’s thick ass and winking pussy were a little above eye level for him, but still quite the sight to behold. She was taking care to keep her tail raised, fanning her moist scent right in his face.

“I’m gonna mount you if you keep doing that…” he warned.

Scootaloo ran her tail under his nose, putting a generous sway in her step. “Then do it, lover boy. With all this magic in us, I’ll bet you could knock me up a few more times over! Hurry up and get that huge cock back inside me, eh? If I have another growth spurt, we’ll know I’ve gotten pregnant again.”

He was atop her before she’d even finished talking.