Betrothal Island

The next day, they had to gather more supplies, food, and building material to maintain their base and existing stores, so Tempest went back to the second spring alone. She brought some gear from the emergency kits, water bags mostly, to store them for their next trip.

After filling the bags, she drank from the spring. It was delicious after all. She sat back on her haunches. She could feel the water settling in her stomach. Then she felt it, a strange sensation in the pit of her stomach. She grunted in annoyance and rubbed her belly, feeling her muscles as she did so.

Suddenly it intensified, and her stomach twisted. She furrowed her brow and sat back on her rear. A shiver ran all over her body, and her groin itched. She looked down in shock as another strange sensation overtook her. Her vagina began to tremble. "What the--?"

She watched in bewilderment as her pussy folded together with the flaps out, as they leaned against one another in a line under her clit. A shiver ran over her as her clit bowed and connected to the line. She shuddered deep within her chest as she felt her pussy seal up. Then something sprang loose. She looked down to feel it pop up, then moaned as something else slid out. She looked down in bafflement at the penis that had unfolded. She had a penis. She wrapped a hand around the shaft and moaned. It was real, and it was full of pleasure. She groaned as her lower body gurgled, then spat out a gasp as something loose and weighty came out. She reached down and her eyes went wide. And now she had a pair of dangling testicles. There was a gurgle, and a feeling of tightness as her slit sealed up behind them. She felt around, then lay back. It was real, she could feel it. Her vagina was gone.

Immediately she seized her cock. It was like a compulsion. She ran her hand over her new member, feeling its curves. She was a lesbian through and through, she couldn't have less interest in stallions. But this…

"Oh, Twilight..." She moaned, as her member became harder and harder. She felt her testicles and grimaced. They were barely full. She thought of everything to make her aroused, but nothing seemed to work. She wondered briefly if her sexuality had been tied to Twilight, and if she couldn't masturbate anymore. "Twilight..." She moaned again. Suddenly she could hear and feel it spray several loads. The goop climbed up her penis and shot out in dribs and drabs.

She waddled her way back, holding her large member. She stopped to lean against a rock and look down at herself. Was she...? She couldn't think about her muscles now, she had to get back to her marefriend.

As she rushed back, she tried to ignore the feeling of her new limb bouncing between her legs. She had to pause again, panting. But was it with exhaustion or anticipation? She felt her testicles. They were bulging and clung to her body. Was she ready to go again?

She felt her foreskin pulling back as she thought of Twilight and groaned in annoyance, fear, and frustration. She thought of Twilight bending over, Twilight pulling the raft ashore, her sleek body slick with sweat, Twilight's firm enormous breasts bouncing as she climbed into her sleeping bag. Twilight's tongue as she licked Tempest's snatch.

She tried to kill these feelings by remembering her guilt, remembering how she had her trapped in a cage, but in this state, all she could think about was Twilight in that bikini she'd made, with a sly grin instead of a defiant frown or a face of fear. "Take me, Tempest."

"Guh!" She felt her cock expand and gout of cum shot up and out. She looked down, her hand covered in semen. She had been masturbating this whole time. It felt so good. For a moment she felt so relaxed. She looked at the goop covering her hand. For a moment, she wanted to taste it. She looked down at her new penis, and her rising and falling chest. Her nipples felt sore.

I have to get back to Twilight. To get help or to fuck her was the question. Maybe both.

She returned to their spring. She stood to her full height. She almost expected– no, hoped– Twilight would suddenly break her habits and take a shower early. No such luck. The punctuality she loved her marefriend for was not doing any favors for her hormones. Tempest looked down at her cock and grimaced, just a little longer.

She didn't think to cover up. Twilight, ever the prude and closet freak in the sheets, would have worried, but Tempest had never had much modesty even before they went nudist. She climbed down into their little home and saw her.

Twilight was at the counter, experimenting with something. Her beautiful sleek arms moved back and forth as she lifted ingredients into a steel bowl. Tempest could see her naked behind. Her beautiful mane went down to above it,

Tempest found her hand working her cock again. She fought and managed to take her hand away.

"uh…Twilight?"

Twilight's humming stopped, and she turned around, holding the bowl. "Tempest? What are you–"

As she saw Twilight's naked front come around, Tempest's erection immediately rose, so fast and so hard that she gasped. "Ah!"

The bowl fell to the ground. "Tempest?" Twilight practically drooled at the sight of her marefriend. "I, um...Whuh--whuh..."

Tempest groaned as she leaned against the table, holding her new member, "Twilight…!"

She couldn't take her eyes off the sway of her lady's waist, the smooth silkiness of her skin. Her eyes widened at the way her breasts bounced as she rushed over in concern. She put her hand on Tempest's free shoulder. "What happened?!"

"I-- I don't know! It just happened!" Tempest exclaimed. "I drank some water from the other spring, and I–"

Twilight crouched down to inspect it. "Well, we have to test this! We…have to…"

"Twilight?"

The princess looked up at Tempest. She put on a sly grin. The same one in her fantasy. "We have to test this."

Tempest's heart stopped. "Twi-- Twi-- I...I..."

Twilight moved Tempest's hand out of the way and grabbed her cock. It was rock-hard. Before she knew what she was doing, she was cupping her testicles and lifting her penis into her mouth.

Tempest groaned, "Oh..." Twilight's tongue played with the underside, running her hand up and down the length. Twilight bobbed her head up and down. It was so long, she couldn't fit it all in her mouth. She suckled and her eyes went wide as Tempest felt her balls churning. Twilight pushed on, holding them up and tingling the area around them. "Twilight I'm going to cum." Twilight looked up at her, then took a deep breath. "Twili--oh, oh...!"

Twilight pushed her head down the length as far as it would go just as Tempest began to ejaculate. Both mares whined and moaned as the white fluid splattered against the back of Twilight's throat. Both mares collapsed backward. Tempest squirted one last blast onto Twilight's tits. They lay back in the grass, propped up on their arms, their legs spread, panting heavily.

"Tastes good," Twilight said, licking some of it off her lips.

Tempest looked at her breathlessly, then laughed. "You've got some on your tits."

Twilight looked down and flushed, "I...uh, sorry. I don't know what came over me!" She silently reached down and picked up the cum with her hand. She considered it for a second, then slurped it up. She flushed again. "Uh...so...how'd you become a futanari? What happened?"

Tempest looked down. She felt her crotch. Her vagina was still gone. "I...I don't know. I was out walking, then my vagina just...vanished. It transformed into this."

Twilight furrowed her brow, "Fascinating, I've never heard of..." As they watched, Tempest's member became hard very quickly. Tempest felt her new testicles churn, and reached down, she didn't know if she was trying to stop it or what. Twilight's mouth fell open. "Tempest?"

"Yes, Twi?"

"I uh..." Twilight spread her legs further, "I need you. I need that in me."

Tempest crawled over her. "Twilight..." She breathed. Having the large, domineering, and powerful mare over her instantly made Twilight wet. She squirmed at Tempest's muscular frame, her tough strapping body. She looked down and shuffled impatiently at Tempest's member. She dragged her member down Twilight's belly, then looked down. She took her new body part and guided it into her lover. Twilight shouted aloud. Tempest cried out as well, shocked by the sensitivity. She pushed further in, moving slowly.

Much to their surprise, despite Tempest's size, the insertion was much easier than they thought. She slid in slowly, Twilight's vagina maintaining its tightness but giving way. It was like they'd had sex a thousand times. If this was what it feels like, we are going to, Twilight thought.
Finally Tempest hilted. She drew out halfway, then thrust again. Again and again, she drove herself strongly, but carefully into her marefriend.

"Harder!" Twilight cried out in frustration, wiggling around the impossible organ.

"I don't want to--"

"Harder!" Twilight shouted.

Tempest did as her lady demanded, and began thrusting harder. Twilight's breasts bounced around and she alternated between holding Tempest's shoulders and keeping her breasts steady. Tempest paused suddenly and leaned down to drink from her tits. Twilight moaned at the brief reprieve and wrapped her legs around her lover. Tempest continued thrusting, "Twi--oh you're so good..."

"T-Thank you..." Twilight garbled, "I love you..." The wonderful sensations going up Tempest's body set her going harder. There was a rushing feeling in her loins.

"Wait...wait..." Tempest intoned, relaxing slightly, trying to hold off as long as possible. She slowed, then started thrusting even faster. Tempest felt her third orgasm with a penis. She felt the warm feeling over her body, then a powerful rushing sensation in her cock. She made to pull out, but Twilight wrapped her legs around her and pulled her close. "Twilight I'm going to--"

"I don't care!" Twilight screamed, "Don't you dare stop!"

"Twilight I'm gonna--" Tempest roared in Twilight's face, thrusting hard into her, each thrust sending a huge spurt of semen into her body. Twilight shrieked, feeling each strike her womb. Both gasped in the suddenly sensory silence. Tempest pulled out, "Well, I've never done that before."

Twilight tilted her head back, "No...kidding," She panted, "But sweet Celestia you're a natural!" Cum dripped out of Twilight's snatch. She groaned and lifted her head, "That was amazing."

“Yeah…” Tempest gasped. They finally calmed down, “But what happened? What is it? Is the island changing me into a stallion?”

Twilight sat cross-legged. Tempest had to avert her eyes from her dripping snatch. “If it were, our breasts wouldn’t be getting bigger. It’s almost like we’re transforming into…better versions of ourselves–ah I mean, a better version of mares. That someone else defined. Not us.”

“Uh…right,” Tempest said doubtfully.

“I’m not sure it means any harm.” Twilight frowned, “But I’m not sure if it’s messing with our heads.”

Tempest nodded, “Good enough for me. We need to find the source of this magic. Wherever it is.”

Twilight nodded back. Her eyes flicked to Tempest’s cock, then back to her face. “Right.”

They were silent for a long time.

"I…I think I love you," Tempest said.

"I love you too..." Twilight murmured.

Tempest sat down beside her. Unconsciously she extended her arm, and Twilight naturally rolled into it, resting her head on Tempest's arm and shoulder. "Really, I think..." Tempest mumbled.

"What?"

"I think I might..." Tempest coughed. "I think I might love you."

Twilight flushed. She felt beet red, or like a tomato. Her heart soared. The confusing emotions she'd been feeling since they showed up...was there more than lust here? "I...Tempest...I mean we’re marefriends…"

Tempest grinned sheepishly, "I know. Weird thing to confess like this. I didn't mean to surprise you...if the feeling isn’t mutual...we can just be friends with benefits…"

"Oh, no, no! I just--" She wanted to scream and shout from the treetops. "I...I'm worried."

"Worried about what?"

Fear ran through Twilight. "What if we don't? What if...wait..." She looked at Tempest's shrinking member. "Did I do this? Did I cause this alteration?"

"I don't think you did. At least not on purpose. It happened after I drank the water."

"But I drank some too! What if it's my magic..." She squeezed her breast, and a squirt of white fluid came out, "There's more of it. I'm fascinated, but--! I'm worried! You just confessed your love for me, and I want to do the same!"

"What?"

"I love you too! But I'm not sure it's real!" Twilight shouted. "I want it to be real, but I don't know if it’s real!"

"Ssh..." Tempest soothed, embracing her, "The island may be doing things to us, but it can't take our souls. There's no love poison here."

"How do you know?" Twilight whimpered.

Tempest paused. She looked down at the mare in her arms, the one she realized she would tear the world apart for. "Because...because...ever since you saved me...well..." She scratched her chin and blushed, "Well, ever since we met you've been kind of cute." She looked away, "But frankly I thought you were with Dash."

"Rainbow Dash?" Twilight frowned. "I don't know what my feelings are for her. But you and I...well, even if we're not that in love..."

Tempest smiled a little, "Even if we're not that in love, there is a bit of love between us." She spread her hands, "And what's a little sex between friends?"

"A little?" She saw something moving out of the corner of her eye.

Tempest looked down, then up at her, lustfully. "Yeah, a little," She said dryly.

They climbed up to the green around the spring, ostensibly to shower.

As they walked, Twilight suddenly grabbed Tempest’s midsection and pulled her down into a kiss. She pushed her tongue inside. Tempest tried to resist, but her tongue’s size was no match for her marefriend’s skills.

Two can play that game. She squeezed one of Twilight's enormous breasts. Twilight shuddered and brought them both to a sitting position. She leaned back. Her marefriend's hands were suitably large, pawing her perky tits. Tempest leaned forward and played with her nipple with her tongue. Twilight pulled her head against her. Tempest's eyes widened, but she began to suckle. As she felt Twilight's warm milk fill her mouth, she reached down and flicked Twilight's clit. The unicorn gasped, and her legs clamped shut. She felt Tempest’s member touching her thighs. Tempest grinned. Still pinned against her, she put her arms under Twilight and rolled, putting her up on her lap. She continued suckling as she rubbed at Twilight's snatch with her free hand.

Almost too soon she felt ooze dripping onto her cock. She switched to Twilight's other breast. Twilight moaned and opened her legs. Tempest's rock-hard erection slid between her legs into her vagina. She clamped down hard, desperately squeezing it. Tempest groaned and straightened up, Twilight's milk finally dried. Twilight tweaked her lover's nipples and leaned against her with a sigh. She began to move up and down.

"Gyaah!" Twilight cried suddenly as Tempest came far too soon, splattering her inner thigh and vagina with fluids.

Tempest flushed pink, the color standing out against her purple skin, highlighting her beautiful opal eyes. "Sorry, I'm not used to this," Tempest gasped.

Twilight giggled and leaned against her tall, muscular goddess. “What is it you love about me?” She mumbled.

“You’re so smart, so beautiful, you…” Tempest smirked, “You’re fun to argue with. And…” Her smirk grew bigger, “I think I love anyone who can kick my ass.”

Twilight straightened up, looking into her lover’s eyes. “You’re so huge, and you’re so strong yet you have such a sensitive side. That little orphan girl you helped…” She launched into an infodumping recount of the little one Tempest helped on her second day after the Storm King’s defeat. Tempest could only sit there and watch, enraptured by her marefriend’s passion.

They showered and got dinner.

They got the formerly soiled sleeping bag and climbed into it. Twilight snuggled into the loving embrace of her lover. Their breasts rubbed against one another. Tempest reached down to cup her ass, and Twilight flushed to feel the unicorn’s erection against her thigh. Pity we can’t go another round.

During the night, their growth accelerated. Their muscles developed and their breasts jumped up several sizes.

The next morning, Twilight awoke next to Tempest. She was on her back, while Tempest was on her side facing her. Twilight felt something digging into her side. She felt around, wondering if it was a stick, then remembered what they did last night.
Tempest stirred, and Twilight sat up. Tempest rolled onto her back and sat her head up. Her morning wood stuck straight up in the light. She took her penis in her hand, and sighed, "So that's still there." Twilight nodded. Tempest looked at her. "You alright?"

"Sorta? I mean we just... can't we control ourselves for a few minutes?"

Tempest sat up a little. "Of course, we can. No matter what this crazy island does to us." Her morning erection began to droop.

Twilight grimaced. "We're changing."

Tempest nodded grimly. "We still don't know where this thing came from."

"Nope."

Beat.

Twilight pushed her marefriend back and straddled her. She pumped Tempest's penis, the foreskin practically snapping down as she did so. She put her mouth over it, sucking and slurping. It felt bigger for some reason. After too short a time, Tempest lifted Twilight and speared her on herself.

"Aah!" Twilight hissed out, "Oh...it feels bigger!"

Tempest screwed up her face in bewilderment, "It does, doesn't it...?"

Twilight skewered herself on Tempest, working her way down. Tempest thrust herself up into her, groaning. Twilight let out a small sound in time with each thrust. She looked down in bewilderment as she finally bottomed out on top of her marefriend. Tempest grinned at her and began to speed up. They screamed together as they came.

Twilight could feel her insides filling up with warm cum, like hot lava. Tempest grunted and groaned as she kept thrusting, feeling like her cock had to deflate to get so much cum out.

There was so much more this time. Twilight felt so full. "Oooh..." She glanced down, "Did...did we get all of it inside?"

Tempest looked down, panting, "I think we did! Wow."

Twilight looked down at herself. Tempest placed a hand over the small of her back, holding her steady. Tempest scooched them back so she was seated against the wall, with her flaccid member against Twilight's snatch, while the scholar was in her lap, facing her, with her massive breasts brushing up against Tempest’s moderately enormous breasts. Twilight flushed. Here she was, seated in Tempest's lap, her large satisfying muscular lap. Tempest ran her hands down her bare purple arms reassuringly, and Twilight made a gurgling embarrassed sound. "You're beautiful," Tempest murmured. She moved her hands up and down, feeling Twilight's thighs, running her hands up her sides, and feeling her curves. She noted they seemed different, but shook it off. She ran her hands up to Twilight's face. She leaned into her hand. Twilight leaned forward and gave her a peck on the lips. Tempest smiled. Her hands moved down to Twilight's breasts and cupped them in each hand. She squeezed slightly, and a tiny glob of white milk appeared. She shifted and slid awkwardly, so Tempest suddenly clamped down hard on one of her tits. “Oh, sorry!”

Suddenly Twilight moaned in ecstasy, far more than she expected. As Tempest ran her hands down her belly, Twilight's moans intensified, in a very curious manner. She squeezed the other breast hard. It squirted milk onto Tempest’s face, and Twilight looked down in confusion. “That…oh, Celestia, whatever you’re doing…oh my!”

Tempest suddenly smirked as she quickly deduced something. She pawed at Twilight's breasts again, a teeny bit roughly. The alicorn groaned and her grip on Tempest's body tightened. She felt juices pouring out of her snatch. "Do you like this?" Tempest said with a sneer to it.

"I..." Twilight flushed.

Tempest straightened up, and spoke in a more husky tone, "Did you like it when I spoke to you like this on the ship?"

Twilight whimpered in embarrassment.

"Princess..." Tempest said, her voice dripping with a sneer as she leaned in close. She felt up her backside, squeezing it. Twilight squealed, "Open up your eyes, Princess..."

"Oooh, don't-- wait keep-- agh!" She moaned softly.

Tempest leaned back and leered at her, cupping her head in her hands, "Oh, Princess, daring to give me orders?"

"I--" Twilight shook her head, "No, a prisoner doesn't give orders...other than to let me go."

"Well, we can't have that, now can we?" She put her hand on the small of Twilight's back and leaned her backward over the bed, kissing her in a strong, domineering kiss. Her tongue forced down Twilight’s, gaining control of her mouth. She reached down with her other hand to support Twilight's belly, then to finger her pussy. She was dripping wet already. No sooner had she reached a few fingers in than Twilight orgasmed.

"Oh!" Twilight splattered across her thighs.

Tempest looked down, then narrowed her gaze at Twilight. "Tsk tsk, Princess. You're going to have to be trained properly." She leaned down to whisper in Twilight's ear. Her sheer presence and her strength made Twilight shiver. "Safeword is quesadilla," She muttered, then when Twilight nodded, she sat up over her. "You're my prisoner, Princess, to do with as I like." She ran her hands roughly, but gently over Twilight's body, feeling it with a sense of ownership. "You will be taught the strength of Tempest Shadow."

"Oh, but I already do...surely a mare such as yourself can see that we are equals."

"Equals, yes, thus I must teach you who is superior." Tempest took her lover's hand and put it on her iron rod between her legs. Twilight's eyes bugged out, and she looked down at it. When she looked back at Tempest though, all she saw was a layer of lust over affection. Her eyes went wider as Tempest swung her leg over her, and sat on her chest. She took her member, and Twilight's hand slowly jerked it off, as she put it between Twilight's breasts. The princess gasped in shock, she'd never considered this. She looked at the head staring up at her. Tempest swung her hips back and forth, working her cock between her breasts. Twilight writhed and twisted, but no matter what, she couldn’t dislodge the rod of pleasure from between her tits. “Come on, princess!”

“Oh!” Twilight squeezed her breasts together. Tempest tossed her head back, her mohawk flapping in the sudden breeze. The tip of her penis brushed against Twilight's lips. She licked up her precum. She felt Tempest's thick legs over her, she felt the intense power. She felt owned, and dominated, yet loved by her partner in their game.

Tempest looked down and leered at her, "You will learn, princess."

She began to massage Twilight's breasts against one another, slapping her hands away. Twilight moaned in pleasure, arching her back and her neck as the pleasure shot through her body. Tempest put her knees in Twilight’s armpits and Twilight felt up her mighty thighs. They seemed bigger. "Mmm...I won't give in," Twilight said in mock defiance.

Tempest leaned forward, rolling herself forward on Twilight's chest. Her breasts bounced, and Tempest felt hers shaking back and forth. Twilight couldn't tell where she was to keep her eyes, her marefriend's intense gaze, or her stunning, gyrating breasts, "You will, Princess. You will be my maiden, not my equal." She grabbed her breasts roughly and squeezed them. Milk squirted all over her front. Tempest grinned, "already your body seeks motherhood." Her words excited Twilight; she reached down to her snatch and began to finger herself, even as she kept jerking off Tempest.

Tempest grabbed her wrist, and Twilight’s eyes went wide. She inhaled sharply. Tempest’s eyes were a typhoon, peering down at her. “I–”

“Not yet, my pet.” Just as Tempest was about to lift off, she felt a churning sensation in her testicles. They were still so new, it was a bewildering sensation, and she realized too late she was about to cum. "You are my maiden," She groaned.

Suddenly she came. Blasts of white-hot semen erupted from her penis and splattered across Twilight's face and open mouth. Both mares cried out as they erupted in pleasure together. Twilight ran through another orgasm, and Tempest felt like she ran through several as she came. “Whoops…” she gasped.

Twilight’s face was half covered in goop. She wiped a stray strand from above her eyebrow and popped it into her mouth. She furrowed her brow quizzically, then her face lit up. “Delicious!”

“Huh?”

“Your cum, it’s delicious!” Twilight said.

Tempest frowned and furrowed her brow, “But…”

“It feels thicker too, ooh…” Twilight groaned and felt her belly. She used her entire hand this time to sweep some of it off her face and licked her hand.

Finally coming down, Tempest leaned down, "You are mine, Princess."

Twilight's eyes were wide and meek; she squealed and orgasmed again. "That was...that was...whoo, that was a great role-play, Tempest!"

Tempest leaned back. Twilight, catching her breath, watched as her slick sweat-covered skin caught the light. "I aim to please. A shame I couldn't hold it in longer."

Twilight felt her belly and smiled, "Well, you gave as well as you could. Could you let me up?" As she stood up, she licked her lips and frowned in surprise. She took a bit of the white goop off her chin and slurped it up. "That's still good."

Tempest meanwhile looked down at her cock. She was surprised to find herself already growing erect again. She was drooping a bit more now that she wasn't facing Twilight, but... Do I have my usual rejuvenation period? She looked back at Twilight, wiping off her face, and turned away. A look at her modest, but attractive and shapely curves made her erection stand tall.

She noted how firm yet squishable Twilight's ass was. But she also saw her hips were wider. Her thoughts now slightly less erotic, she cleared her throat. "I think we're both getting bigger. You're taller than you were yesterday."

Twilight frowned. She seemed less upset than before, as she looked over herself, "It's fascinating. The change is so slow, yet so powerful." Twilight noticed Tempest, and pointed, “You’re wider too. Your muscles are thicker, and your biceps are larger.”

Tempest looked down at herself. Indeed, they were. Her firm muscles were already at the peak of fitness before landing here, but she seemed to be moving past that point. Suddenly, she had a lewd idea. She flexed, “See anything you like? Princess?”

Twilight sighed as they settled in for another session of passionate lovemaking. But she loved being dominated by Tempest.

They searched during the day for the source of the magic, but the island had so many nooks and crannies, there was only so much they could explore without getting lost. Twilight resolved to make a map.

After dinner, in the setting sun, on a ridge overlooking the horizon, they sat together.

"After all we've done, I'd like to do something for you."

As they took in each other, they noted the differences that had been made already since coming to the island.

Twilight’s alicorn beauty had been dramatically intensified. She was curvier than ever, not too wide and not too thin. Her breasts had doubled in size, and her hips had widened noticeably. Tempest had grown several centimeters. Her breasts had been moderate beforehand, but despite her increasing musculature, they seemed to be trying to catch up to Twilight. It was a losing battle, but a losing battle with her was enough for any sports magazine cover. Both of them had gotten taller and wider, but Twilight was falling behind rapidly.

They stopped leering and began kissing. Twilight straddled her marefriend. She ran her hand over her body, exploring every nook and cranny. She felt her broken horn gently, felt the fuzz of her mohawk. She put her hands on her cheeks and stared into her eyes for a long time, before running her hands down her neck and across her majestic shoulders. Tempest giggled a little as she touched her armpits. Twilight smirked, then moved her hands down to her sides. She put a hand on her distinct iron-clad stomach, all muscles. She felt her breasts, making Tempest groan in surprised pleasure, and let out an eep! As she felt movement behind her. "That thing just has a mind of its own, doesn't it?" Twilight mused.

She slid down Tempest's body and took her erection in her hand. It came from her clitoris but looked like a regular stallionhood to her. Not that she had many occasions to refer to. Tempest gritted her teeth and grasped the ground with one hand. Twilight smirked and cupped her marefriend's testicles. They felt normal to her, as far as she knew. Tempest bit her lip, and held a finger to her mouth, "Are you done?"

"Not quite." Twilight leaned down and put her lips over the member. Tempest groaned, and immediately put her hands on Twilight's head, not forcefully, just an acknowledgment. Twilight thought for a moment it was larger than before, but shrugged and kept going.

"That was..." Twilight's eyes widened. Tempest grinned sheepishly as before their very eyes, the member grew more and more erect, rising back up to its original hardness.

Twilight wiped away some drool. She clambered atop her marefriend, as if she was emerging from the cold, and immediately plunged herself onto her. Tempest roared aloud and grabbed Twilight's hips. She lifted herself up and down again. "Mmm!" Tempest grunted, her eyes clamped shut. She moved her hands up Twilight's upper sides, then to her shoulders as she began to thrust. Twilight put her hands on either side of Tempest's head as she threw her head back, and continued to hump into her. Tempest thrust back up into her, returning the favor. It was like a seesaw, they were caught in this rhythm as they learned each other's speeds and preferences. Each time they made love it felt like a whole new adventure again. Tempest didn't know where to put her hands. She squeezed Twilight's breasts, making her purple-skinned lover above her cry out. Milk splattered across Tempest's upper chest and breasts. Twilight's hair was loose, and dangling over Tempest. She pulled Twilight down into a kiss, mushing their breasts together as they pounded away at each other.

"Oh...oh...oh..."

"Twilight, I'm gonna--"

Twilight slammed herself down with three massive thrusts, and Tempest groaned out as she began to ejaculate. Twilight screamed with pleasure as she was filled, clamping down on Tempest's cock and spraying her with her juices as she orgasmed.

She collapsed onto her, fighting for breath. Tempest wrapped her up in her big strong arms and kissed her. Twilight shoved her tongue inside and they mashed with one another for space. Tempest's flaccid member fell out of her marefriend as they lay there, just holding one another.

As they dozed off, watching the sun go down, the island intensified its work. Their bodies continued to be monitored and transformed. Both mares shimmered and began to grow. Both of them increased their dimensions by exactly one size.

The next day, they went back to the house for a shower. They dove into the spring. Tempest rested her chin on her marefriend's head. She noticed Twilight was taller again. She was back up to under Tempest's chin.

Twilight felt her breasts. They were practically overflowing now. "They're bigger..."

"So are you," Tempest commented. She put her chin on Twilight's head, "As frightening as it may be...I still love you."

Twilight turned and kissed her. Tempest reached up and pawed at her breasts. Twilight moaned into her mouth and shoved her tongue in. But Tempest pushed back. She squeezed Twilight's breast and squirted milk out. "Oh, you're making a mess, pet," She sneered and pulled Twilight against her.

Twilight gasped in delight, "I didn't mean to, mistress!"

"You're going to make one anyway!" Tempest squeezed her breasts and milk covered Twilight's front. She pushed her back against the wall of the pool. She shoved her tongue deeper and deeper into Twilight's mouth, continuing to squeeze her breasts. She mashed their breasts together and felt an odd sensation in her nipples, but she was too excited to care. Twilight's eyes went wide as Tempest lifted her shapely buttocks and began to push her member inside her.

She rolled her over and bent her over the edge. "You are mine, princess!" She marveled at Twilight's supple back, and her smooth purple skin. Then shoved her member inside. Twilight arched her back leaning into Tempest. Tempest pulled her close and squeezed her tits, "Come on, make a mess!"

Twilight screamed and squished her tits herself. She felt each of Tempest's thrusts, bouncing up and down and squirting white liquid from her sharp nipples. "I am!"

"Not enough!" Tempest gave a hard thrust and shoved her forward into the grass. She screamed out and grabbed at the grass for stability. Tempest thrust her hips upward and gasped, "Prepare for it!"

She shuddered as she came.

An hour later, they were out walking again, this time Tempest was a bit nervous. But Twilight was still nervous too. "You know what the perfect cure for this is?" Tempest asked.

Tempest twitched her new member. She lifted Twilight up and put her against the rock. She lifted her member and pushed it into Twilight. They groaned aloud as Twilight wrapped her arms around Tempest, seeking purchase. "Oh, Celestia..." Twilight murmured.

Tempest began to move, driving her hips into her marefriend, "Indeed..." Tempest's breasts jiggled slightly, but the forward and back motion kept Twilight's bobbing. They kept moving and moving, the passionate feelings rising as they found the right rhythm.

As time wore on, they kept growing. Their muscles and bodies transformed. But they were too caught up to notice. Tempest panted, thrusting her cock deep inside her mate, "Come on, almost there..."

"Tempest ah! Tempest, Tempest..." Twilight moaned. She held her massive breasts, milk squirting everywhere. There was more of it than ever.

"I'm...I'm gonna...!"

"Inside!" Twilight shrieked, "Inside!"

Tempest thrust and could hear the spurts, feeling them enter Twilight's womb. The nerd screamed aloud, throwing her head back as she orgasmed.

Suddenly both shouted as a feeling like fire ran over them, and both orgasmed once again.

"Tempest, what...?"

Tempest's muscles had developed. She looked down in bewilderment at herself, feeling her taut and toned abs. They'd rounded out far more. Her breasts were bigger. She was more than a bodybuilder, she was becoming larger. She squinted at Twilight. The smaller mare was even curvier than ever. Her waist had drawn in. Her rear was bigger and more shapely. Her boobs had inflated again. "I..." Still, inside Twilight, she began to grow more erect.

They worried about what the island was doing to them.

Their explorations continued to reveal nothing. And despite their changes, they only seemed to make them hornier and not less. As they changed, they found it increasingly difficult to stay away from each other. Twilight would find herself going out to find Tempest whenever she went off to find materials. Tempest would more often than not meet her coming back the other way. They made out quite often and made love every time they had one of these exchanges.

That evening, while making dinner, Tempest walked up and grabbed her around her waist. She shoved Twilight over the table and lifted her generous ass. She rolled her over and felt her breasts. "These are huge!"

"Aah--I know!" Twilight looked up at her, "So are yours!" She pinched and pawed at the massive breasts above her, around Tempest's arms. Tempest grabbed her hips and leaned her head back, thrusting in over and over.

She pawed at her breasts as she thrust. Twilight lifted her hands, "Oh no, princess," She pinned her hands above the unicorn, "You are mine." Twilight should have felt in danger but her arousal just skyrocketed.

"Tempest–– Ah!"

Suddenly, Tempest rolled her over. They both fell to their knees beside the table, but now Twilight was on all fours.

“What are you doing–?!” Twilight’s words cut off into an incoherent wail as Tempest thrust firmly into Twilight's third hole for the first time. Her eyes went wide, "Tempest! Oh– oh– Celestia!"

"Twilight!" Tempest groaned, "Oh Twilight, ugh, you're so tight..."

Twilight had never had anything this big before, let alone anything back there. Carnal desires and possibilities filled her mind as Tempest shoved her member deep inside. She rolled her own body back against Tempest, driving her deeper and deeper into her anal cavity. They established an equilibrium, painfully stretching one another out. She was so tight, so pleasurable, Tempest came very rapidly.

She erupted into Twilight's ass, filling it up with cream. Twilight collapsed on the floor while Tempest stumbled back against the wall, falling on her bare muscular rear. Twilight rolled around on all fours, crawling to her marefriend. She grabbed her penis and stroked it, "I need you inside me again, that was amazing!"

Tempest was surprised by the forwardness, even after all this time, and was forced into a kiss. She felt her erection rubbing against Twilight's belly. "Ah, finally!" Twilight straddled her hips and impaled herself on Tempest.

"Aah!" Tempest shouted and weakly began to respond to Twilight's rough thrusts.

"Come on, Tempest, you've got another, don't you?"

Tempest grinned, "Of course I do!"

Their horns charged with energy as they pounded one another, coursing through their bodies almost unnoticed. In their collective orgasm, the pleasure was multiplied tenfold. Tempest's cock was squeezed like it was in a vice as it splattered Twilight with what felt like gallons of cum. "Aah!" Twilight screamed as she felt her stomach seeming to fill up. She swore her hand on her belly moved.

“What the–?” Tempest groaned through pleasure. Both of them looked down to see a large light-purple bulge between them.

“Aah!” Twilight screamed again, as her belly literally inflated with cum. She looked several months pregnant by the time Tempest was finished.

They finally collapsed apart. As they took in air, and the sight of their sweat-stained counterparts, their eyes fell on Twilight's belly. She'd been filled up so much that her stomach was bulging out. She groaned and held her stomach, "Wow, feels like...I don't know what!"

They looked at her bulging gut in disbelief. Tempest gaped, "You…you look pregnant!" Her erection wanted to grow again, and she noted it seemed to be bigger. It had to be a trick of the light though, it was finally spent.

"I..." Twilight gasped. She felt her stomach again, "I felt it expand! What is this?"

"I don't know! You're the magician!" Tempest gasped, and touched her horn, "Our magic! We were casting!"

Twilight lit up her horn, and after a few tries, managed to get a spell out. "Phew...I'm not pregnant!"

Tempest sighed with relief. "That's--"

"I'm just filled with your...seed."

Tempest had never felt her erection rise so fast. She put her hands over it and winced, "Celestia, I'm sorry..."

"That is the strangest turn-on..." Twilight mumbled.

"Oh, get over yourself, princess!" Tempest snarled. It was almost painfully erect.

Twilight's eyes widened, then the words processed. She grinned flirtatiously, yet nervously, "Make me."

Tempest's eyes widened. She looked down at her belly. "Should we...?"

"It's just cum, I mean...I'm not pregnant, my spells should work. It should work itself out." Twilight leered, a little more confidently, "So. Make me get over myself."

Tempest hesitated, then crawled over and patted her belly. "Consider yourself dominated."

Twilight grinned mischievously, "Or, the commander should consider herself...taken." She leaned forward and kissed her.

She pinned her down on the table. “How about both?”

The next day, Twilight’s stomach was back to normal. And she was several centimeters taller and still more attractive. With little else to do, Twilight was studying the spring. She thought she could get a hot tub made from the heat source in the center. She’d already carved out a hole, she just needed to figure out how to get the water…

She heard a noise behind her, and saw Tempest, returned from an expedition, wearing a loincloth. “Did the weather change?” Twilight asked, trying to avoid checking out her crotch.

Tempest folded her hands behind her back formally. There was no smile. "Do you remember when we were on the Storm King's ship?"

“Yes…” Twilight said.

“Speak when spoken to, princess,” Tempest said. A crack appeared, “...Same safe word.”

“Oh! Oh.” Twilight put down what she was doing and put up her hands, “Yes, of course, commander!” She paused, breaking character, "I wish you still had your suit."

"Well, when we get home, we're going to have fun." Tempest grinned predatorily, “I had another change today. She snapped the loincloth line.

Twilight's jaw dropped. Her member must've doubled in size. "That...how will that fit?"

Tempest looked down, "We'll figure it out. And if it's too much, just let me know." Twilight nodded, and Tempest's softer voice vanished. "Princess...I've taken your kingdom. Now I will take you."

She felt a sudden urge and pushed Twilight to her hands and knees. "Service me, princess."

As Twilight suckled on her lover’s member, Tempest gripped her horn, using the table for support. She felt an odd buzzing in her hand, and noticed in the back of her mind, Twilight’s horn vibrating.

When she came, Tempest groaned and lifted Twilight up. Twilight put her arms around her girlfriend and kissed her. Twilight forced her mouth open with her tongue, and Tempest's eyes shot open as her own cum poured into her open jaws. She cried out, muffled, her eyes going wide.

She swallowed. She wasn’t kidding about how good it was! “Just for that…!” She pushed Twilight down onto the soft grass and aggressively forced her into a kiss. “I’m going to fuck you into the next lifetime!”

“Oh, commander, please–egh!” Tempest was already bringing her enormous length to bear.

As she thrust into her lover, Tempest's horn was arching and sparking. Twilight could almost see lightning traveling down her muscles. Another thrust. She realized Tempest's cock was widening her, reshaping her!

"Tempest, you're...you're changing me!"

"What?"

"Our magic," She groaned, and whimpered when Tempest stopped, "Our magic! Something to do with our magic is changing us!"

Tempest made to pull out, "I--"

She hit her shoulder, "I don't care! Keep going!"

She pounded into Twilight. The changes weren't subtle now, they could feel their bodies rearranging themselves, redesigned only for each other. And they loved every second of it. Tempest was molding Twilight just as Twilight molding Tempest, changing her to fit her needs. Their hips and waist were altering, shrinking, or widening to just the right size and depth for Twilight to wrap her legs around Tempest, and Twilight for Tempest to feel like her cock was made specifically for the beautiful princess.

"You're mine," Tempest hissed, thrusting into her. "Your body is mine, can't you feel it changing?"

"Yes...oh, yes, Tempest!" Twilight cried out. She could feel her pussy being molded to Tempest's shape. "Yes, and you're mine!"

Either the game was turning her on that much or Tempest was way too good at it. Tempest kept pushing. Her length was so immense and so powerful.

"Do it, Tempest!" Twilight cried.

Tempest thrust into her, slamming with all her might with gritted teeth.

Tempest hissed with exertion, then felt the long grinding feeling of her cum. She sprayed into Twilight's womb, giving her an immense feeling of delight. The sheer amount felt like it was bulging out Tempest's penis. Then another came, and another. Twilight rubbed her stomach, "Oh, so full...!"

Tempest kept coming, and cumming. Her eyes widened as she noticed Twilight's stomach begin to inflate. Both were shocked, "I...can't...stop...!" Tempest cried. She pulled out and covered Twilight in cum. Still, she came. She glanced around, then noted the hot tub area she'd dug, waiting to be filled. She aimed her member at it and sighed with relief, grunting as she kept cumming. She didn't know how long it was until she finally came to a halt.

They had a steaming tub of cum.

“What the–?” Tempest demanded.

“Wow!” Twilight exclaimed. She crouched near the pool, “Guess we’re digging another, then.”

Tempest crouched by it, expecting a stench. But as it tasted good, it also smelled good. “Celestia, how did I produce that much?!” Tempest demanded.

"I'm almost disappointed I couldn't take it all," Twilight commented.

"I'm not looking forward to clearing out that stink come morning," Tempest muttered.
Twilight hummed, then her horn glowed. The white fluid sparkled. "Now it'll stay fresh until it evaporates. We can rotate it if..." She smirked and reached down to stroke her marefriend's member, "you're willing."

Tempest grinned and rubbed her marefriend's belly, "Only if you are."

They fell asleep spooning, with Tempest's member safely within Twilight's snatch.

All the while, the island continued to change their bodies. They didn't notice the dimensions of the cum bath deepening, or widening. The spell over the tub changed as well. The fluid inside changed from cum to something else, mixing together. They were prepared for the final transformations.
dinner

Tempest awoke to feel a jet of pleasure on her chest. She had grown in her sleep again. Her breasts still weren't Twilight-level, but they were still voluminous. That wasn’t the most shocking thing. The shocking thing was that Twilight was suckling from them. And milk was coming out. She groaned as another jet of milk erupted.

"I'm lactating...?" Tempest muttered.

Twilight looked up at her, "I...uh..."

"I'm lactating?" Tempest repeated. She sat up quickly. Twilight squeezed her other breast, and a small squirt of milk erupted. “How is that possible?”

Twilight stopped. “I don’t know.”

Tempest sighed, then looked at Twilight. "You know what happens to naughty prisoners."

Twilight blinked, then nodded, "Oh yes, Tempest, I do."

"Then prepare for your liquid breakfast."

"Yes, Tempest."

Twilight climbed off the bed onto all fours. Tempest's morning wood rapidly hardened into a proper erection. An idea overtook her. She drove it straight into Twilight’s mouth.

She could feel her throat widening as Tempest thrust into her, slowly but surely widening her. But she went further than usual. Her jaw cracked and she let out a whine of pleasure. Tempest pulled her further onto her enormous member, stretching and widening her. "Let's test alicorn endurance..." Twilight's eyes widened as she was pulled on further. Her esophagus stretched and expanded. Jets of white hot cum shot into her stomach. She was perfectly stretchy and accommodating. Her body was already quite accommodating with alicorn magic, but it wasn't often that she could see it like this. Her eyes widened and rolled back in her head as she could hear the cum pumping down her throat in her ears. Each one made her throat bulge slightly. She kept swallowing and swallowing, closing her eyes. She was able to take more and more of Tempest's cum even as the quantity kept increasing.
Finally, the mare tapered off, and she fell to her knees. Twilight fell on her haunches and looked down. Her eyes were wide in bewilderment at her stomach. Just past her enormous breasts, her belly bulged out. She clambered forward into her arms, and Tempest leaned against the bed. Twilight lay against her, Tempest's cock between their legs. "That was the most I was able to take so far," Twilight murmured.

“And soon you’ll take much more.”

She yelped when Tempest lifted her and pushed her off the bed. She pushed her onto all fours, and Twilight quivered in anticipation.

Then she felt it come into a hole she had fantasized about but hadn’t anticipated her third whole. Twilight screamed Twilight shouted in shock as she slid in. It felt like she had molded Twilight's anal cavity to fit her cock. “You’re molding me again…” She moaned.

"All the better for you to be my fuckdoll, my dear," Tempest said as if reading her mind. She leaned back. Twilight let out a series of yelps as she thrust in and out.

Finally, she screamed as her anal cavity expanded.

As they came apart, Tempest noticed something. “Did…did your ass just get bigger?” Tempest asked.

Twilight felt her rump. Indeed it had. “I blame you.”

XXXXX

That evening they looked at the pool of cum. "So...why'd we make that?" Twilight asked.
Tempest shrugged, "I'm not sure." Twilight flushed heavily. She stepped over to the steaming cum, still hot from the spring, and dipped her toe into it. "What are you--?"

Twilight crouched down, put her legs into the cum, then lowered herself into it. "OOOHHH..." She moaned, "This...!" She was splattered up to her breasts in cum. "This is amazing!"

It was a wide pool, wider than Tempest thought. What was going on? Tempest walked over and crouched beside it. Twilight smirked, then took a deep breath and sank into the liquid. Tempest stuck her finger into the goo. It had the viscosity of toothpaste and the consistency of something thicker than water. It was almost like dough, weirdly, but looser. "This isn't semen...at least, not exactly," She muttered to herself. It felt nice, like hand ointment. She rubbed her fingers together. The goop stuck to her fingertips and didn't seem to come off.

Just then, Twilight reemerged just in front of her. She whipped her head back, splattering Tempest's front with goo, and wiped off her eyes. "Tempest, this stuff is amazing." She pulled her hair back behind her.

Tempest tilted her head a little, noting there were droplets on Twilight's naked skin, but something seemed strange... She flushed herself. "That's...um..."
"Sexy?" Twilight guessed.

"I was going to say gross--"

Twilight grabbed her marefriend's arm and hauled her down into the cum. Tempest's open mouth caught a full dose of the goo. The pool was deeper than she expected. She stood up, coughing up goo, and painted entirely white. Her mohawk was squashed with the weight of the goop. She tried to wipe off her eyes and looked down at herself, "What is this stuff? This isn't normal cum!" She tried to wipe it off, "I hope it washes out!"

Twilight kissed her. They licked each other's mouths as any thoughts beyond each other washed away. They broke, and Twilight reached up to dab at some goop on Tempest's forehead with her finger. She sucked it off, "It's fine, we've got a spring!"

Tempest sighed, "Alright, it doesn't seem dang...erous..." She trailed off as Twilight took her finger out of her mouth.

"What?"

Her finger was completely white. Tempest reached out and held it. She felt her erection under the surface at the feeling of her marefriend's saliva but rubbed at Twilight's finger. "It's...it's been bleached."

"What?" Twilight looked down at herself. She rubbed at her arm, wiping off the white goo. Underneath lay nothing but white skin.

They looked at each other. They reached out and felt the other's faces, to make sure they weren't seeing things. "It's completely dry!" Tempest murmured. The only color between them was their eyes. "Twi, what's happening?"

"I don't know! I didn't cast any additional spells! It has to be the island!" She felt Tempest's mohawk, "Even your hair roots have been bleached!"

"Yours too! Otherwise, you look like Rarity." It was like the cum had simply caked itself onto their bodies wherever it touched. Twilight felt her hair roots and looked at Tempest.

"I'm sorry, this is my fault." Tempest pulled Twilight close, putting her hands around her waist and looking down at her ivory face. She kissed her, tasting a berry flavor of her own cum.

"It's alright, Twi. I'm here, you don't need to worry about protecting me." She tried to smile, "Besides, this one is on me."

"Tempest...the inside of your mouth is white."

"So's yours." Tempest looked around, "And this pool is a lot larger than I dug. There's magic here. It's swirling around us."

"Yeah, I can't identify it..." Twilight felt the waves disturbed and felt something brush against her leg. She looked up at Tempest. She flushed, even through the white. All worries about the pool being poisonous vanished as she felt her juices mix with the pond's goop. She pulled herself up and kissed Tempest. Tempest kissed back very eagerly. As they made out, the outline of their bodies seemed to become more defined. Tempest's hair straightened out. Twilight's shoulder muscles became more visible.

Twilight pulled her down further, both stepping down into the pool on steps they didn't know were there. They went up to their necks in cum. They finally broke, gasping. The paper-white mares looked at each other. They felt their arms moving under the cum. "Want to cum in my cum?" Tempest breathed, "Or whatever the hell this is?"

"Oh, sweet Celestia yes."

She levered Twilight up slightly and pushed her penis into her. She grunted with the exertion and had to push the pool's liquid out of the way. Twilight grabbed her arms and threw her head back. Tempest thrust up into her plaster-white lover, making their breasts bounce. Twilight could see Tempest's ab muscles outlined in white, every angle of their bodies was outlined. Their manes had turned white. Their entire bodies had been bleached white, seemingly permanently. Somehow though, this didn't worry them as much as it should have. Tempest's penis felt larger than it had ever been, and Twilight arched her back and moaned aloud. It felt like her body was contorting to fit Tempest's shape, now more than ever. Both their bodies felt so bouncy and they loved every minute of it. They were getting bigger, their assets inflating. With every thrust Tempest unintentionally fed more goo into Twilight's body. The large mare's frame felt a tingling sensation at her rear, and the tip of her penis, but she was too distracted to notice. Their thrusts sloshed the waves back and forth, and each time, the goo seemed to thicken on their bodies. They lost their definition again. They were harder than usual, even with Twilight's preferences, Tempest put her powerful hips into the job. Just as Twilight began to feel the pulse of cum, Tempest pulled out and sprayed her with cum. The jizz sprayed out from under the waves like a water cannon as Twilight moaned with pleasure and bewilderment, riding her orgasm. Tempest leaned her arms against the dirt on either side of her lover and watched the white goo lapping at their waists, their genitals under the waves.

"Tempest...something...I feel strange." Tempest and Twilight looked at each other. They were caked in cum, Twilight looked like she'd been hit with a can of paint on top of her bleached skin, and Tempest looked like she was wearing a set of snow pants. Suddenly a force tugged at Tempest, making her lose her balance. Twilight grabbed her hand, and they both fell into the goop again. Both inhaled a ton of goop. Tempest contorted as it felt like something was prodding at the tip of her penis and her backdoor. Twilight felt the goop at her various holes as well. Their mouths opened and it forced its way into their bodies like snakes despite their resistance, pumping into them and filling the pair inside and out with goop. Their horns arced under the liquid as magic swirled around them. Something moved around inside as more cum was pumped into them. It felt like they were inflating, bulging out with slime. They felt like they gained several pounds. They were being stretched beyond belief. Instead of pain, they were filled with a sensation of shock and pleasure. their ears were muffled, they couldn't hear their own moans.
Both struggled under the waves, then got their feet under them. Twilight pulled Tempest out of the goo as they coughed and sputtered.

As they emerged they felt a sensation shoot up their bodies like flash paper. Thick layers of white sticky goo clung to them, weighing them down. They looked like white balloons. But at first glance, their bodies seemed to show no sign of inflating. They looked seemingly normal. They climbed out of the pool. Twilight put up a field to keep it off the grass, and together the mares jumped into the water of one of the hot springs.

Instantly, the white goo hissed, leaving a wide pattern of dust in the water. Streaks of purple color appeared on their bodies as they sloshed toward the waterfall. Patterns appeared all over their skin as they exposed their ivory-white bodies to the water. Twilight scraped at her hand, and grinned with relief as her purple skin was revealed under the cracks. The cum came off with the water, Splintering off like an eggshell, or ice. She rubbed at her whole body, seeing her purple skin appear through the cracks. "It washes off!"

"Twi...?" Tempest muttered.

"I'm so happy, thank Celestia," Twilight breathed as she saw her arm come out of its shell, perfectly intact, "There's no burns or anything."

"Twi..."

"It was so strange." She pulled her hair back with both hands, "I'm glad we're back to normal! Or as normal as it gets around here."

"Twilight!" Tempest barked.

"What?" Twilight demanded. Her eyes went wide with shock as she took in Tempest's body. She looked at her reflection in the water and gasped.

They scrambled out of the water, and their new bodies were revealed.

They were like goddesses. They had both gained nearly a foot in height. Tempest was at least Celestia's height, if not more, seven feet tall. Their curves were accentuated, they were so much...brighter in a weird sort of way. They were so lustrous.

They looked down at themselves, "W...what happened?" Tempest felt her hair and looked at her reflection in the water. Their hair was so much more vibrant and bouncy. Tempest's mohawk had been straightened back to its mainland perfection, and then some. It was taller, with a brilliant shape almost like fire with a few attractive frays splitting off to either side. Twilight felt her hair and looked at it in the water. It maintained its traditional appearance but was as smooth and conditioned and as perfect as Rarity's. She twisted a lock of it, and it didn't tangle, it moved so perfectly. She studied a lock of it, then moved on to explore the rest of her body.

"Uh...wow." Her shoulders were sharp but descended smoothly. Twilight couldn't see past her new massive breasts. She hefted them, each seemed like the size of a watermelon, yet they stood out firmly without a need for support, and put little weight on her back. They were almost as big as Celestia's and just as attractive. each squeeze sent a wave of pleasure across her body. She looked at her arms and gasped. When she flexed, a powerful muscle emerged from her upper arm, but when relaxed, her arm was as sleek and smooth as it had ever been.
Tempest's frame was huge and lustrous, strong and hardened. She was astounded by her broad muscular shoulders and her taut sinewy arms. She was jacked and sleek. Her chest was toned and tough and bore a pair of enormous breasts that were smaller than Twilight's but still would make her the envy of anyone. Tempest felt her breasts too. They were soft, yet firm, jiggly yet didn't require much support when she moved. She squeezed them and gasped. They were entirely natural. Even if it was magic, her new breasts didn't have anything inside them. As she squeezed, a squirt of white milk sprayed out, giving her intense pleasure. They were filled with something, then.

Twilight heard her marefriend gasp and saw the white fluid. Curious, she squeezed her own humungous breasts. They also felt completely natural. She shuddered as a pressure like a firehose erupted from her nipples. She released her grip. Twilight twisted in place, running her hands down her body. She was incredibly curvy, with a powerful hourglass shape. Her waist was drawn in, and her hips were quite wide, with an enormously satisfying bubble butt to match. Her stomach muscles pleasantly outlined her belly attractively with a cute belly button. Her whole body was muscular and slender, but smooth and sleek, hiding her strength.

Tempest was a contrast. She had dense well-defined musculature. She had an enormous six-pack. Her waist went in less than Twilight's, making less of an hourglass shape, but still with a dense and shapely rear. Her hips went out to meet her thick and chiseled thighs, the well-defined muscles standing out and making distinct lines down to her knees. And between her legs was her new penis. Her testicles had doubled in size, and her cock must've been a foot long. She reached down to feel her cock. It went erect almost immediately. She began to stroke it with an overwhelming urge.

Twilight ran a hand down her rear, feeling her smooth dense thighs. A shudder ran over her. She twisted and put a hand on her side, slowly turning in place as she studied herself. She realized she was putting on a show for Tempest's throbbing erection. She felt herself practically flooding at the sight of her marefriend's new body.

They were like goddesses, challenging the royal sisters for their beauty. Their skin was luscious and smooth. And their muscles were so defined. Their hips went out, their waists were drawn in. Twilight's breasts were nearly the size of Celestia's, while Tempest's were Luna's size. Twilight had some muscles, but her belly was accentuated more than her muscles, standing out attractively with a cute belly button. Despite their size increase, they were both still so sleek, they weren't overly plump. They were perfectly proportional.

Twilight smiled and swayed her new wide hips. She brought her hands up and moved them down from her chest, running her hands down her waist, across her hips, and back down to her thighs. She turned in place again, then winked at Tempest.

"Oh god..." Tempest's eyes shot open as she began to ejaculate. Two shots of cum painted her face and shoulders, blinding her. The next salvo covered Twilight's entire upper body, and Twilight could hear more bolts sailing past her. Tempest groaned as she felt her body levering up more cum for her. She fell to her knees in shock, still pumping even after it was gone.
When Twilight cleared the cum from her eyes, she noticed Tempest's erection hadn't gone down. If anything, it had gotten harder. She licked her lips and moved forward. She bent down to get ready to suck Tempest off, but the larger mare grabbed her hips. She looked up at her and grinned. "Allow me, Princess." She pushed Twilight back, earning a yelp, and she rolled back onto the grass. Tempest pulled herself forward and before Twilight could even get settled, dragged her tongue over her snatch. Twilight shouted aloud and grabbed Tempest's head, putting her heels in the backs of Tempest's shoulders. She could feel the amazon's intense power, her majestic frame in her back muscles. Tempest licked her clit, and moved her tongue to her lower lips.

Twilight sprayed her lover with her cum as she orgasmed, "Temp--Temp--Temp-- I-- Ah!"

She shrieked as Tempest kept up the pressure through another orgasm.

Tempest licked and blinked in surprise at the taste of the juices. It wasn't like anything she'd had before, Twilight had a unique taste but this was amazing. She kept at it, drinking it in. "You're so good, Twilight."

Finally, Twilight collapsed back, utterly exhausted. Then she felt goosebumps as Tempest crawled over her. She felt like a wild animal, yet totally civilized. Tempest was like a war that way as she loomed over Twilight. Twilight took in her overwhelmingly powerful body, her new lustful shape. She could feel Tempest's cock running along her legs. She was so big, so immense, they weren't at equal height. She felt Tempest breathing over her and looked up into her new beautiful face. Her mohawk was illuminated in the light from the fire and the crystals, giving off an impression of power. "My love..." she breathed.

Twilight impatiently wiggled her pelvis. She wanted to be pounded, dominated, completely and utterly filled. "Please..."

Tempest leered at her, "Not yet. Princess..." Tempest lowered her head and squeezed one of Twilight's breasts ever so gently. a squirt of milk jumped out of her nipple in an arc. Twilight gasped. Tempest looked at her, "Sensitive, are we?" She lowered her head further and squeezed again. It sprayed into her open mouth. "Ah!" Tempest cried, and looked up, "Princess, your milk is divine."

She leaned down and wrapped her lips around her nipple. She began to suckle. It was sweet and warm, the best milk she had ever tasted. Twilight groaned, moaning and whining at the pleasant sensation of the milk flowing out into her lover. Tempest switched to the other. Twilight came against her thigh. The princess gasped, was she always this easy to please? Their sensitivity had increased just that dramatically.

Tempest could drink this all day. But Twilight had had enough teasing. Tempest raised her head and lifted herself over Twilight. She put her hands on her arms, gently pinning her to the ground. She straddled Twilight's thighs, feeling their soft and firm muscles underneath. Twilight felt the weight of her partner above her. "I am going to destroy you, princess," Tempest growled.
Twilight gasped in surprise

Tempest took her cock in her right hand and dragged it down Twilight's groin. The head caught on her clit briefly then slid by, going down over Twilight's pussy. Twilight struggled in her grip. "Princess, so needy," Tempest sneered. Both felt a wet liquid sliding down Twilight's front; Tempest's new penis and new body now had more precum than the amount of cum she had when she first grew the organ. Tempest's domineering grin grew. Then very gently, she slid her member into her pussy.

"Ah!" Both shouted out in ecstasy as the two organs joined. It was like lock and key, or yin and yang. Tempest pushed her wide long member into her marefriend, aided by the copious amount of fluid she'd already generated, but it was somehow easier than either of them had expected.

"Tempest--I-- Oh--" Twilight moaned. Her pussy lips moved apart as if this were their only purpose, to move aside only for Tempest's cock. Tempest gritted her teeth in astoundment. She was as pleasantly tight as could be, absolutely perfect. it was practically sucking her in. It was like they had been made for each other, and for once, both mares honestly believed it. But it was like moving into a brand new house, it was new, needed to be tested out, and have all the kinks worked out. They groaned as Tempest's member pushed into Twilight's tunnel, hitting new depths it had never hit before. Twilight's eyes widened as she felt the foot-long member reshape her vagina. Tempest threw her head back as Twilight's tunnel reshaped her cock.

Finally, Tempest hilted, she grabbed Twilight's shoulders, and she began to thrust. Twilight's breasts bounced uncontrollably, "Harder, Tempest! Harder!" Tempest gritted her teeth and thrust harder. Twilight's hair flailed around, and she held her breasts, squirting milk. She wrapped her legs around Tempest, trying to get some measure of control. She could feel her thick back muscles, her robust musculature. Her mighty pounding hips thrust into the smaller divine mare, the hulking woman excited by her lover's words. They were both in a cloud of pleasure, reaching orgasm together.

"Twilight, I'm..." Tempest groaned, "Be ready prince-- aaah!" Finally, Tempest came. Twilight could hear the squelching of her Tempest's cock as it began to shoot straight up into her womb. Tempest roared as she thrust rapidly into her lover, each time spraying enormous shots of cum into her. Each one seemed accompanied by an orgasm. Twilight's eyes went wide then rolled back in her head. How much was there? She looked down to see her stomach ballooning out.
"Temp--Tempest--"

Tempest grinned and pulled her to her, still thrusting, "I'm not stopping. You're mine."

The words sent shivers down Twilight's entire torso, ending at her hips. Tempest kept thrusting and thrusting. "Tempest, I'm so full, please--"

"Princess..." Tempest breathed through gritted teeth.

Twilight felt three orgasms come in conjunction with those words. She lay back as she felt her body fill with semen. Her toes curled. Finally, Tempest came to a halt. She relaxed, panting, and looking down at her destroyed lover. She was still inside Tempest. Her eyes widened as she looked at Twilight's bloated stomach. "Twilight, I'm sorry, I don't know what came over me, I--"
Twilight grabbed her by the horn and pulled her down for a kiss, the large amazonian mare groaning in surprise. Twilight released her and looked down. "It's alright, I'm here. And now I guess I can take it." She grunted in pain as she shifted, and glanced down again, "...Maybe not every time, though."

Tempest chuckled, "You look pregnant."

Indeed, Twilight looked down to see her new belly stretched taught. She looked more than nine months pregnant. Tempest looked down and pulled her foot-long cock out. Both mares groaned in pleasure. A faucet practically turned on as Twilight lost much of the cum. Under the spray of cum, Tempest realized she was finally flaccid. "Well, that's one way to handle that."

"But what about this?" Twilight asked, running a hand over her belly. As she did so, both mares felt a tingle of magic. Twilight's belly rapidly deflated, returning to her perfected shape. It felt like she'd eaten a huge meal.

"...Well that's convenient," Tempest finally said.

They both snickered at that and caught each other's eyes. Twilight sat up, her breasts jiggling. Tempest's eyes flickered down, then back up. As if reading each other's minds, they stood up to study each other.

They looked at each other. They had literally been reconfigured for sex. Tempest had Celestia's height, but she had Luna's curves and breasts. She was an amazonian sex goddess. Twilight looked down at herself. Her physique had soft supple curves, arguably a feminine physique, but she was still so strong underneath. She was more of a nerdy sex goddess.

"What's happened to us?" Tempest asked, looking at her forearms.

Twilight turned in place, looking down at herself, "I'm not sure. You were right, that pool isn't semen. I don't know what it is."

Tempest scratched her head, "What do you think this place might be doing to us? Aside from the obvious."

Twilight gave her a sidelong glance. "I...I don't know."

They felt the urge to kiss just then. But the sticky ground at their feet made them wonder. They separated to gather supplies for dinner.

They lay in bed side by side, thinking. Levered up on a cushion of moss and pillows, Twilight looked down at her new body. She ran a hand over her new skin, across her soft belly. "What am I?" She murmured.

“You’re my marefriend,” Tempest said and kissed her.