The first thing she felt was the soft bedding pressing against her cheek when she shifted her head. Lightning Dust let her eyes flick open, her mind trying to figure out where she was.

Muddy memories from last night began to crystalize in her mind. She recalled being at a bar, one of her usual haunts. A quiet, charming stallion had made his way to her, striking up a conversation.

Initially, she hadn’t been in the mood, but something about him had been compelling, and she’d soon moved with him to a secluded corner.

That was where things got…odd.

“You looking to get lucky tonight?” she’d asked.

He’d smiled. “Well, perhaps after a fashion, but not tonight. You’re…not exactly my type.”

She recalled the flash of anger she’d felt. “What the hell does that mean?” In her mind, she was every stalloin’s dream – toned body, well-kept mane, an ass you could bounce a bit off of. Sure, perhaps her tits were a little on the small side, but you couldn’t have a pair of big wobblers if you wanted a toned tummy with it.

Not naturally, at any rate. And Lightning didn’t trust some shady unicorn in a back alley to perform some of the less-widely-known spells that would have made it possible. She’d heard the stories of what happened when it went wrong.

“Oh you’re attractive,” he’d added, perhaps sensing he’d irritated her. “But I prefer someone a little more…mature.”

At the look of confusion on her face, he’d leaned in and smiled. “Tell me, Miss Dust…are you familiar with the term MILF?”

A knock at the door brought her out of her memories, and she started, pushing herself to her feet to look around the room.

The furnishings were simple, yet well made, clearly hand-crafted and placed in a tasteful fashion. Various paintings hung from the walls, while a pair of cozy looking chairs were placed near the fireplace in the corner. One wall was covered with bookshelves, which groaned under the weight of all kinds of tomes placed on them. Yet the centerpiece was the enormous bed she’d been sleeping on, which looked big enough for four people.

Another knock broke her from her examination.

“What?” she asked, not caring if she sounded harsh. She didn’t know where in Tartarus she was, and even for a mare who enjoyed fucking stallions every chance she got, waking up like this was unusual. She always preferred to be in control, and that was definitely not the case here.

“Are you decent?” a familiar voice called.

“Am I…” she muttered. “Look, you better start explaining how I got here, or I’m going to the police!”

The door opened, revealing the same stallion from the night before, a sly smile on his face.

“Why, Miss Dust, you’re here because you accepted my challenge and followed me home.”

She frowned. “What challenge? And who are you?”

“Oh, dear, I did warn you about consuming so much alcohol,” he tutted. “I’m Finer Things. What do you remember last?”

She scowled. “You asked me if I knew what a MILF was.”

“Ah, good, so there’s not much to remind you of,” he replied. “Put simply, I prefer a mare with…shall we say, a body that’s a little more on the motherly side. When I explained that to you, you snorted and said that all stallions preferred bodies like your current one, and that ‘becoming a saggy old mare’ meant the end of all sexual attentions.”

He chuckled. “And for some, perhaps that’s true. I won’t deny that your current figure is attractive…but it could be more attractive with some changes.”

More of the prior night was coming back to her. “And you told me I’d look better with tits like a bloated cow, wide birthing hips, a fat flabby ass, and trading my hard-earned abs for a gut like a pregnant sow,” she completed.”

He laughed now. “Well, I don’t think I used such terms as those…but yes, more or less.”

“And…” she paused, mentally freezing. “And for some reason, I didn’t throw you across the bar.”

“That’s because, deep down, the thought appeals to you, on a primal level. You told me as much yourself.”

“I did not.”

He shrugged. “Well, the Lightning Dust of last night did. Perhaps you’re no longer her. At any rate, thatLightning Dust made some decisions that the Lightning Dust of today is going to have to cope with.”

“Like what?”

“Well, later in our conversation, I asked you how you’d like the opportunity to become a MILF. You snorted and told me that you weren’t exactly the right type to raise a foal, which I don’t disagree with.”

She felt another flicker of anger, but it was tempered with the knowledge that she did feel that way. “Go on.”

“So I offered you another option. You see, there are a small group of us that all share similar tastes. We got together with some expert alchemists to develop…a potion, really, one that will slowly transform the drinker’s body to become like that of, well, a MILF.”

“And you think I’m going to drink that?” She snorted. “Buddy, you’re crazy.”

“Well, that’s what I was talking about when I said you had some decisions to cope with.” He pointed to the table, where a large empty potion bottle sat. “You already took it last night.”

A chill ran across her back. “What?”

“You also signed this,” he continued, approaching her while holding out a scroll. “Called it the MILF Challenge.”

As she read the agreement, which indicated that she promised to try the experiment, he added, “You also told me that you expected to win. As you’ll see at the bottom, I promised that if you did win, I would pay you the sum of fifty thousand bits.”

It was her signature at the bottom, the little lightning bolts over the I’s just like she always did.

“And what was the challenge?” She looked down, her wrinkled clothing not revealing any changes. “I don’t look any different than I did last night.”

“It takes the formula some time to take effect,” he replied. “And it needs a catalyst, namely, sex, or some sort of sexual activity. Otherwise it simply passes out of you after a few days, no harm done.”

“And what exactly does it do?”

He smiled. “Like I said, it makes you motherly. Your body, rather. But I don’t want to spoil too much of the surprise.”

She stared at him for several seconds. “Fifty thousand bits?”

“Yes.”

“And all I have to do is…” she read the contract again, “Get through at least three stages of this MILF Challenge, and then decide I want to change back to my old form before going through the fourth?”

“That’s correct,” he replied. “You’ll have to abstain from sex for a few days, but you’ll be back to your old self after that, just fifty thousand bits richer.”

Her eyes narrowed. A few days without sex would be hard, but not impossible. “This seems too easy, even for me. Are you really prepared to pay out?”

“Let’s just say I’m confident you’ll see the appeal once you’re on the other side,” he replied. “And if not…” He moved to a cabinet she hadn’t seen, and opened it. Her jaw dropped upon seeing the multiple bulging bags of bits sitting on the shelves inside.

“I’m prepared to be a little poorer for the experience,” he finished.

In the end, it wasn’t a decision at all. Fifty thousand bits was fifty thousand bits.

“Fine.”

Gesturing to the bed, he smiled. “Shall we get underway?”

She reached behind her back, starting to pull her shirt off. “For the most fun I’ve ever had making fifty thousand bits? Absolutely.”

Tossing the shirt aside, she cast a single glance down at her uncovered torso. Petite, perky breasts capped with darker green nipples and areolae greeted her. The room was slightly on the cool side, making her nipples harden. Below that, her washboard abs stuck out on her toned tummy and narrow waist, the envy of every bloated mare and lazy housewife at the beach, or so she thought.

She tugged her pants off next, revealing that she’d also gone without panties last night. Only a single tuft of yellow pubic hair rested above the slit of her pussy, neatly trimmed in the shape of a downward arrow to point at the goods. She felt briefly self-conscious about having done that, but quickly suppressed that sentiment. She didn’t care what he thought – she just wanted his money.

There was no need for her to look back to know her ass was as firm and toned as ever. Turning around, she flexed onto one hip before looking back over her right shoulder, putting a smoulder in her gaze that usually was enough to get any nightly lover to turn to putty in her hands.

But Finer simply stood there, placidly smiling – and more importantly, still dressed.

“Aren’t we going to fuck?” she asked.

“In time, yes,” he replied. “I believe in helping the lady enjoy herself first.”

“Fine.” She crossed to the enormous bed, lying on her back and spreading her legs. “Then come eat me out already.”

“Certainly.”

In truth, she didn’t have high hopes for this part. Most stallions were terribly inept at the practice, and she usually ended up having to finger herself to finish by the end. But she’d give him a chance.

The first inklings she got that this situation might be different was how he started. For one, most stallions dove in like it was a pie eating contest, sucking and slurping and thrashing their tongues about wildly.

Finer, however? Started with gentle kisses on her inner thighs, slowly making his way inward to her honeyed valley. She was about to complement him – begrudgingly, but compliment nonetheless – when he surprised her with a gentle lick that sent a tingle up her spine.

“Oooh…” she moaned, feeling her temperature start to rise almost immediately. Fuck, it hasn’t been that long, has it?

From her position on the bed, she couldn’t see him smile with the knowledge that the potion was already going to work. He licked again, drawing another twitch and moan from her. Seeing her outer lips begin to moisten, he took a deep breath and dove in for the kill.

“Oh fuck, oh fuck, oh fuck!” she shouted as he expertly devoured her pussy, her muscled thighs closing about his head as his tongue positively drove her wild. Just when she thought it couldn’t get any better, his tongue found the little nub of her clit, brushing against it and sending another surge of pleasure throughout her body.

Then he hit it again. And again. And again.

As his tongue drove her wild, she was too out of it to notice the first outward changes were already occurring. With every surge of pleasure from her clit, her breasts grew just a little, swelling from small protrusions, to big enough to fill a palm, to a handful, and beyond.

Peeking up for just a moment to make sure things were proceeding, he took another deep breath, jammed his face in between her thighs, found the right nubbin, and sucked on it, hard.

Lightning’s mind exploded with pleasure as she quickly surged into her first orgasm, her thighs locking around Finer’s head and holding him in place, not that he had any intent to pull back just yet. Her breasts, which had been steadily growing, now ballooned outward, wobbling and jiggling on her chest as she bucked and writhed on the quickly dampening sheets.

More critically, changes began to occur in her mind, subtle ones, but changes nonetheless.

Finally releasing his head from the grip of her thighs, she lay there panting, a well-fucked expression on her face.

“Where…where did you learn to do that?” she asked, once she'd finally caught her breath.

He appeared in her vision then, grinning. “Lots of questions, my dear. And practice.”

She felt an uncharacteristic urge then, a desire to give to him as good as she’d gotten. Normally, Lightning was not a generous lover, but the mental changes she was undergoing were seeing to that, and subtly enough that she didn’t even realize they were occurring.

Moving to sit up, she was struck by the odd undulation from her chest, which got her to look down, her eyes widening.

“What…the fuck!?” she shouted, her hands flying to grasp her greatly inflated breasts. But her anger was immediately tempered by the surge of pleasure she felt as her hands groped the new titflesh, which was extremely sensitive.

“Four rounds, remember?” he said. “Each round will change your body in a new way.” He smiled as her hands continued to rub and squeeze her new assets. “Still want to continue? I’ll let you out now if you wish, though there won’t be any payment in that case.”

Half distracted from the sensations coming from her new tits, she still managed to scowl.

“I don’t give up that easy,” she replied, taking her hands away from her breasts to reach for his belt. “And you’re overdressed for the next part.”

He allowed her to remove the belt and undo his waistband, unable to avoid smirking at the thought of what she was about to find. Already quite healthily endowed, the portion of the potion he had taken – which he had not disclosed to her – had taken him from gifted to Cadance-blessed.

As she pulled his boxers down, her eyes grew wide at the thick slab of stallion meat protruding from just below his waistline. Easily as thick as her forearm, and nearly as long too, his cock bulged with veins, the medial ring only challenged for dominance by the fat flared end at the tip.

Her eyes lidded as she inhaled the first wisps of his musk, the scent tingling the pleasure centers of her brain.

“Hungry?” he asked.

She looked up, grinning. “Starved.”

Then, surprising even him, she opened her mouth and took a full half of it in in one go.

“By Celestia,” he groaned, the potion’s changes greatly heightening his own pleasure. If he hadn’t had considerable self-control, it was likely he’d have cum right then. As it was, he intended to enjoy the use of Dust’s throat for at least a little while.

She looked up at him, her eyes playful as she inhaled through her nose, then she started to take even more of his cock into her throat.

“Oh, Lightning,” he breathed, his hands coming to rest on her head.

“Mmm?” she mumbled.

“If you’re really hungry, you shouldn’t delay on my account.” Then, with a single move, he pulled her head forward, shoving the rest of his cock into her mouth and down her throat.

She felt the old anger flare as her nose pressed into the fur above his cock, but it was tempered by how good it felt to have her throat filled with stallion meat.

No, not just any stallion meat. Her stallion's meat.

A small part of her wondered where that thought had come from, but she brushed it aside, and focused on sucking off every inch of Finer's cock. He'd done good things for her, but she wanted to show him who the real boss still was.

His hands continued to run through her mane, gently rubbing in circles on her head, which drew a soft moan of pleasure from her. While she still intended to win, it was hard to think much on it when she just felt so good.

Two can play at that game, she thought, bringing one hand up to gently start fondling his heavy balls.

The self control he'd been so proud of quickly evaporated. Her throat simply felt too good, her tongue expertly working his shaft as she sucked and slorped his cock, and the fondling was just the last straw. Breath control, muscle clenching, none of it was going to be enough.

“Light…Light…aaagh!” he shouted, as his control released.

Lightning felt his flare swell in her throat, felt the first waves of cum traveling past her lips before they exploded into her throat. As deep as his dick was inside her, she had no choice but to swallow, his rich cream immediately bringing about the second set of changes.

From his position above her, Finer had the perfect vantage point to watch as Lightning’s hips started to widen, much like those of a mare who’d popped out a couple of foals. Her thighs grew thick, and, while he couldn’t see it, he knew her ass was growing as well. Every new wad of cum brought a little more growth with it, and the potion’s changes to his own body meant there was plenty of cum on tap.

For her part, she felt the odd growing pressure on her cunt as her swelling thighs started to press inward, and she felt something odd around her tail, but otherwise she was focused on the task in front of her.

Or in her, rather.

Finally, slowly, the flow of semen tapered off, and she felt his flare shrink enough to pull herself off his softening length. Just as he exited, one more spurt of cum shot out, landing on her chin. She brought a finger up, wiping it off and sucking it off her finger.

“Mmm…” she cooed. “Best tasting protein shake I’ve ever had.”

“F…fuck,” he said, the sensations finally having broken through his gentlemanly exterior.

“Momma knows how to make you feel good, doesn’t she?” she said, her voice husky. Then her eyes went wide. “Uh, I mean – “

“All normal,” he replied, winking. “Ready for me to make both of us feel good this time?”

She wanted to say no, but the heat that had been building inside her was intensifying, and her pussy was quivering at the thought of being filled with cock. She didn’t just want him to rut her, she needed it, badly.

But she wasn’t about to beg for it.

“You think you’re up to the challenge?” she said, smirking. The smirk grew wider as she saw his spit-slathered shaft begin to harden and rise once more.

“I’m going to break you,” he promised.

“You’re going to try,” she corrected, flashing her teeth.

He surprised her by shoving her back onto the bed, sending her new tits wobbling about, the sight of which made his cock twitch. Grinning, he grabbed her legs, lifting them up and setting them onto his shoulders, giving him both access to her perfect pussy and giving him a chance to feel up her newly fattened ass.

She noticed something was off, but before she could think too much about it, Finer’s cockhead was pressing at her entrance, filling her mind with lust once more.

“Ready?” he asked.

“Fuck me,” she commanded, her usual arrogant tone softened by a new huskiness, pure need in her eyes now.

“With pleasure,” he replied.

Lightning had been with a lot of stallions. As a general rule, she preferred bigger cocks to small ones, but nothing too big.

At least not before today. A whorish moan escaped her as his mammoth cock began to spread her apart, every part of her canal being rubbed and brushed as he slid deeper and deeper. She could feel the bulging cock veins inside her, and it was positively delightful.

When they reached the medial ring, she was nearly ready to tap out, fearing for the first time that she’d finally found a limit. There was simply no way her pussy could take it. Then he’d simply pushed past it, drawing a lusty scream from her as she clawed at the bed sheets, pleasure and pain temporarily dominating her brain beyond the capacity for rational thought.

She felt his head prodding at her cervix as he hilted himself in her, a grin on his face.

“Ready to surrender?” he asked.

“F…fuck no,” she replied, panting. “Just waiting for you to get started.”

“As the lady desires.”

He pulled himself back, once more meeting some resistance around the medial ring, but the pain was less now, and she relaxed a bit, allowing him easier access.

Before she could prepare herself, he shoved it all back inside. His heavy nutsack slapped against her ass, making her ample cheeks wobble a little, but she hardly noticed. All she cared about right then was being full.

He built to a steady rhythm now, greedily watching as the outline of his cock could be seen pushing against her still washboard abs. His hands squeezed and groped every inch of her ass, savoring how soft and pliable it was now, almost none of the former muscle tone in evidence. The ass of a mare who lounged around being fucked all day, with the tits to match.

And now it’s time to give you that mommy tummy, he thought.

For Lightning’s part, she had brought her hands to her breasts, tweaking her left nipple with one hand while she squeezed her right tit with the other, heightening her own pleasure as Finer pounded her into the mattress. This was easily the best sex she’d ever had, and she didn’t want it to stop, her moans growing louder and longer as he continued.

But Finer’s endurance was only so good, and she heard the grunts about the same time she felt his flare start to swell inside her.

With one final thrust, his cock pierced her cervix, flared even larger, and started to gush cum into her body.

The sensations drove her into her own explosive climax, her pussy clamping down hard on his shaft, milking him for every drop as her own nectar spurted out onto his coin purse. The pleasure from the cum was so great that she'd barely started to come down when she flared into yet another climax, the fire of her libido growing even hotter than before.

Panting, Finer watched as her belly started to swell with his seed, her abs stretching at the unexpected pressure from behind. Then they started to dissolve, her taut tummy being replaced with a soft layer of chub that swelled out, her navel deepening for the first time ever.

Her narrow waist then grew wider, eliminating any trace of an hourglass figure as the potion took the cum and converted it to soft, womanly fat.

Lightning noticed the changes…but she found she didn’t care. So what if she was a little wider? She was older, after all, and a mare couldn’t stay rail thin forever. Besides, it drove her stallion wild, and she craved his attentions.

No, wait. What the fuck am I thinking? a small part of her demanded.

We’re thinking that that dick is worth any price, the rest of her replied.

Satisfied that the third stage was done, he pulled his softening length out with a splorching noise, a few stray gobs of cum following him out, pooling on the bedsheets below.

“F…fuck…” she panted, letting her legs drop, sending jiggles through every part of her body. One hand wandered down to her waist, pinching the new layer of chub there, prodding the beginnings of love handles that she was starting to sport.

Fifty thousand bits! that small part of her mind screamed. You’ve had your dick, now get out before you’re lost forever!

She snorted, no longer caring about something so trivial. Money couldn’t replace how womanly she felt, how fulfilled she felt. And, while she’d always been a horny mare, the level of horniness she felt now was richer, like a slow burning deep inside of her. The thought of abstaining from sex for even a day was more than she could bear. No, she needed dick, and she needed it now.

“Hey,” she said, getting his attention.

"Yeah?"

“Wanna fuck my ass next?”

Panting from exertion, Finer’s eyes widened, but he nodded. “I…thought you’d never…ask.”

Grunting a little from the effort, Lightning rolled over, getting to her hands and knees. Her breasts swung underneath her, making soft plapping noises as they did so.

Finer took his cock in one hand, gently guiding it to her back entrance. In truth, he wasn’t sure what this was going to do to her – none of his fellows had ever gotten a mare past the third stage.

While his cock was still plenty slick with his and her fluids, he was about to press inside before he wondered if he needed to prepare her. He didn’t want to hurt her, after all.

“Finer?” she asked, breaking his concentration.

“Yes, Lightning?”

“Inside me. Now.”

“If you say so,” he replied.

At first, neither of them thought he was going to fit. Lightning’s ass was tight, and his cock was, simply, huge. She leaned down onto her breasts, bringing her hands back to pull her asscheeks apart, loosening her hole just a little while he steadily pressed…and then, with a soft pop, his flare slipped inside her.

It wasn’t as good as her pussy, a fact that surprised neither of them. But the feeling of kinkiness more than made up for it.

She winced as his medial ring pressed at her entrance, a few tears leaking from her eyes.

“You sure you want to continue?” he asked, genuine concern filling his voice.

“Yeah,” she replied, gritting her teeth for a moment before forcing herself to relax. “Fill me up, honey.”

Finer felt a tingle in his body at those words, unaware that the potion was making some changes in his own mind. The lust he’d felt since the start was tempered with something approaching genuine love. She was no longer just something to sate his urges, but…she was his mate.

And he cared about her.

Deeply.

Patting one buttcheek appreciatively, he pressed inside, then quickly bottomed out, drawing a lusty moan from her.

“Good?” he asked.

“Uh huh,” she replied. “More. Faster.”

He pulled back to the medial ring, then shoved his length back inside once more, his nuts swinging to lightly plap against her pussy, making her coo in pleasure.

“Still good?”

“Damn it, Finer, just rut me!” she practically howled. “Punish my naughty ass with your massive cock!”

Pure desire overrode the last of his restraint then, a grin appearing on his face. "Yes, dear."

And then he set about giving her exactly what she asked for.

The air was filled with the smells and sounds of sex, from the plapping noise his nuts made as they contacted her dripping snatch, to the grunts he made as his cock was squeezed by her ass, to the moans escaping her soft lips. Faster and faster he went, determined to last as long as he could.

But Lightning had other ideas.

“Finer?” she said, between coos of pleasure.

“Honey?”

“Breed me,” she said throatily.

Finer, having been close already, tipped over the edge. Roaring in pleasure, he slammed himself into her ass just as his flare swelled, painting her insides with the largest load of cum yet.

His eyebrows raised in shock as she managed to reach between her legs to begin fondling his sack, as if she wanted to milk every drop of cum from him that she could.

As cum filled her ass, the potion got to work completing the final changes. The rest of her muscle tone faded as a new layer of softness appeared all over her body. Her lips plumped a little as her chin softened, giving her a much more sensual appearance. Her tits, ass, and belly all swelled even larger, her once dainty nipples and areolae stretching and growing as though she really had borne a few foals of her own.

While neither of them could see it, Lightning could feel her vulva growing puffier as a little mound of softness appeared above it, completing her transformation into the thing she’d never expected to be.

The small voice inside her was silenced as her mind fully embraced her new age and body.

For his part, Finer underwent some physical changes of his own. Streaks of gray appeared in his hair, not too much, but enough to make him look distinguished. His own muscles softened a little, looking less like a well-trained buckball player and more like a reasonably fit middle-aged stallion that still took some time to train, but spent more time devoted to his mate.

The enhanced cock remained, a gift of the potion meant to make up for the other changes.

Said cock finally softening, Finer pulled out of her ass, then helped her get off the bed to her feet. She wobbled uncertainly as she took her first steps, though she quickly got the hang of it, and she slowly sidled over to the mirror, his and her cum dripping from both holes, something Finer found extremely erotic.

She still remembered how she’d looked just a little while ago. But, as she stared at the new figure in the mirror…she found she had no desire to go back to it. Sure, she was looking decidedly plump now, and sure, her heavy tits sagged more than she might have liked, and sure, her ass was way too large for her taste…but she felt happy. Happy in a way that not even flying had been able to provide.

Finer appeared behind her, wrapping his arms around her as he bent into kiss her cheek, his hands rubbing her soft tummy.

“You look beautiful,” he said, kissing her again.

She snorted. “You’re just saying that because you want to go again,” she teased.

“No, no, I think I’m a little too tuckered out,” he admitted, meaning it. “But tomorrow? Definitely.”

A faint gurgle stopped both of them, and Lightning looked downward, only to realize she couldn’t see her belly past her tits anyway.

“Dinner?” he guessed.

“Please,” she replied. “And then maybe we can break out the strawberries and whipped cream later.”

He licked his lips. “I can hardly wait, babe.”

A soft plap drew their attention.

"I think I'd better shower first," she offered, realizing she was still leaking cum. Lowering her voice, she added, "Would my handsome stud would like to help wash my big ass?"

Finer felt a surge of love toward the mare that had become his dream girl. "Anything for you, my Dust."

Author's Note

This is my first time posting anything particularly sex heavy anywhere. I’m aware it’s not perfect, but hopefully it wasn’t too bad and you were able to find some enjoyment from it.