“I must say, while I want to support the two of you, I'm not entirely sure I'm comfortable with such a... drastic plan.” Rarity looked concerned across the small private chamber of their princess friend's tree castle. She spoke as much out of a sense of obligation as of real worry. It was her solemn duty as big sister and guardian to make sure Sweetie stayed safe, even if she did trust Twilight's magic... mostly.

“I've, um... tried a lot of things,” more than Fluttershy now wanted to admit, “but that time your magic, Twilight, changed me into a vampire fruit bat—I don't think I've ever felt closer to another creature. With how much I've changed since my foalhood, I feel like I've almost become a different creature since then. I don't think reminiscing or role playing any more can help me find what I'm looking for any time soon, but, if you'll give us this chance—if you think it will work and you don't mind, I mean—I know we'll both come to understand each other better.”

“The theory behind the magic is relatively sound.” In spite of her worry, Twilight Sparkle couldn't help but reassure her friends of the reliability of her craft, having tested it over the last few months in a more controlled setting. “That's not what concerns me.”

“Please, Twilight!” the small ivory filly begged. “I want to understand her too.” Sweetie Belle exchanged a soulful gaze with the pegasus.

The plea was unnecessary, but Twilight took it for the final confirmation she needed. She shook her head. Lovebirds. “Alright. Remember, the magic will swap most of your essential traits and talents, your unconscious selves, as well as most of the semantic memory that make each of you... you, at least under most circumstances. Being ponies, the exchange should feel more natural than it did with the bats,” Twilight held eye contact with Fluttershy, “but you can still choose to resist it.” Twilight looked between the two. “Your episodic memory, all of your life events and experiences, will remain unchanged and undetected by anypony but yourself. Naturally, you'll each experience some physical side effects as well: nothing too jarring, but, I expect, some regression or hyper-development and certain trait swapping like what happened to you, Fluttershy, with the bats. You'll remain yourselves, in your own bodies, but you'll think and act like each other and you'll take some of each other's physical traits.” Twilight summarized. “If it's concerning at any time to either of you,” Twilight reassured, “come to me, and I'll change you back.”

Fluttershy and Sweetie Belle each nodded silently.

“Is everypony ready?” Twilight looked between her three friends.

Two unconventional lovers plus Rarity nodded.

The end of their day in each other's horseshoes drew to a close, and Fluttershy and Sweetie Belle sighed as they finally rested next to one another in the living room of what had become their cottage rather than just Fluttershy's shortly after they'd received the unexpected blessing of Sweetie's parents.

If they hadn't known each other, each pony might not have recognized the other. Fluttershy's coat had paled somewhat; Sweetie's had yellowed ever so subtly. Their eye colors had swapped, and each pony's mane behaved more like her partner's did on a normal day. The swapping of their traits was far from superficial, however.

“I forgot how hard life is without knowing your special talent,” Fluttershy complained far more vocally than usual, her voice resembling a tired Pinkie Pie rather than her typically demure self. Fluttershy peered back at her own blank flank longingly while Sweetie Belle listened patiently. “I feel way more confident in some things, but like a klutzy bumbler in others, um... n-no offense.”

Sweetie shook her head, understanding. Before she could say anything, Angel appeared and thumped impatiently next to the butterfly-marked little unicorn. “Oh, dear,” Sweetie Belle sounded more like the shy filly from her class, Dinky. “J-just a moment.” The cream-coated filly vanished before Fluttershy could offer to help, but returned only half a minute later. Rejoining Fluttershy, remembering, despite her subconscious, she was small enough to lean into her fiancee, Sweetie Belle let herself rest against the filly-minded adult next to her. She sighed again, but smiled. “It's wonderful having a cutie mark,” Sweetie spoke to herself as much as to the mare she'd borrowed it from, and she tittered softly and grinned excitedly for a moment at her flank, “but...” she attempted to empathize with her pining, immature mate, “I never knew you were always so busy thanks to it.” The adult-minded little filly looked up maternally at her very special somepony. “You must be exhausted by the end of most days.” Sweetie blushed brightly and looked down. “It's no wonder you like to, uhm... relax a bit in the evenings,” she hinted not too subtly.

At this, Fluttershy's ears perked and she grinned slyly down at her small lover. “I may not remember very well what puberty feels like right now, but I am sooo ready to... relax a bit.” Fluttershy bounded to her hooves eagerly and stumbled, almost falling over onto the filly. “Sorry.” She giggled and blushed sheepishly. Being uncoordinated wasn't a new sensation, but it had been a long time since she'd grown used to her adult limbs. Still, with Sweetie's subconscious, Fluttershy somehow expected herself to lose balance at any sudden movement and managed to catch herself.

Sweetie Belle chuckled softly and looked half-lidded at her mare, rising to her hooves as well. The little filly headed upstairs ahead of Fluttershy with a swish of her tail, leading naturally, the way Fluttershy usually did.

Unable to remember how to fly, Fluttershy stumbled a couple of times on the way, but, in her exuberance, still made it first to her bed after she'd entered the room behind Sweetie. She buried her muzzle in her own pillow and inhaled deeply for a moment before stopping and wondering at herself. “Is it weird that I'm turning myself on with my own scent?”

Sweetie shook her head after she'd hopped and struggled onto the bed with a helping hoof from Fluttershy. “Not even a little bit. I, umm... I admit I couldn't keep my hoof from between my own stifles when I visited my own room at the boutique earlier today—not with your sense of smell. When I'm myself, of course, your scent turns me on. But... enough distraction.” Sweetie Belle's dulcet tone suddenly sounded predatorial. “I'm going to teach you what it's like to have your innocence taken,” Fluttershy's pupils contracted at the filly's promise, but she smiled, thrilled, “and, as long as I'm smaller than you...” Sweetie Belle gulped suddenly at the building intensity of her urges and the threat she heard herself making almost compulsively, “it's not going to be too gentle.”

“Y-yes ma'am,” Fluttershy gave the adult-minded foal what she knew she wanted, reveling in the feeling of her own vulnerability. Fluttershy was bigger still, despite their physical changes, and it wasn't the first time they'd taken turns with the dominant role before, but it felt so much different, actually being the innocent one for a change, not just acting the part. “I—please, yes.”

Sweetie Belle smiled crookedly. Already, she noticed that sex lacked something that it normally had for her, novelty maybe, but more. She understood yet another reason that Fluttershy favored the dominant role: excitement. Tonight, she knew, she had to embrace it. “Spread it...” Her eyes suddenly became fierce and her smile vanished. “N-now!” The foal's stare locked on the innocent yellow mare.

Fluttershy suddenly felt genuine fear that nearly drowned out her own natural excitement. Trembling, she reminded herself that the foal loved her, that deep down she was kind, but she needed this to release so much pent-up aggression. Just like Fluttershy did normally, Sweetie would stop before it went too far, she trusted. Swallowing, Fluttershy laid back and slowly opened her back legs to the filly. She tried again to give Sweetie the fantasy she knew she craved subconsciously. "Use me... please."

Sweetie Belle shuddered at the request, enlivened and empowered after a day of catering to the will and whims of others. Every cruel urge and frustration inside of her struggled at once to take over. She didn't know what hit her, but she didn't fight it. “You useless blank flank,” Sweetie scoffed, knowing it would hurt the submissive mare, but forgetting how much, too lost in her revelry to care.

Fluttershy gasped and frowned. She hadn't expected the backlash.

“Just try to shut up while I polish my hoof in your retarded foal-hole.” Sweetie Belle relished and hated the mare's trembling frown and the sudden shimmering in her hurt eyes as she set herself between her yellow hind legs. Wanting more pain, she placed a small hoof over the blushing vulva of her partner. It was almost dry. Knowing her own former physical development, this came as no surprise to Sweetie. It also came as no surprise that Fluttershy yelped in pain as she forced her small front hoof roughly inside.

“S-stop! P-please!” Fluttershy trembled and fought to regain her composure. “No—I mean...” she struggled against the urge to protest. “'M sorry... M-ma'am. Please, make me useful. I don't—” she choked and sniffled “—don't wanna be a useless blank flank. Do... do anything you want to me.”

Sweetie Belle's grin widened, and she pulled out her hoof. “Fine,” she scoffed, reminding herself suddenly of Diamond Tiara. To her surprise, she found it didn't bother her. Maybe it would later, she thought vaguely, but, for now, the guilt seemed easier to accept—embrace, even. Self-hatred fueled her fire, only causing her to act more the villain.

The filly felt the odd sensation of flapping non-existent wings until she realized she'd have to position herself without the aid of flight. Straddling the yellow pony's muzzle while facing her barrel, Sweetie pressed her small pussy and anus against the mare's mouth. Rather than ask, the filly kicked Fluttershy's head with a back leg to prompt her to start licking.

It hurt a little physically, but not nearly as much as it hurt Fluttershy's already-feeble self-worth. Having forgotten just how cruel her urges sometimes were, Fluttershy began to sob like the filly she was mentally. Had she gone this far with Sweetie before? Would she ever? No, she thought. But maybe, if she were small and knew it wouldn't hurt Sweetie as much... that must be why Sweetie was being more rough than she'd usually be. Through her trembling and tears, she licked halfheartedly at the foal's labia.

“Get inside.” Sweetie ordered the innocent pony impatiently and pressed the full weight of her core down on her, grinding her small precocious mare parts against lips and teeth. When Fluttershy's tongue tentatively wormed its way inside, the little filly sighed and began to gyrate. Sweetie's enhanced, mature fluid ran hot and abundant across Fluttershy's lips and down her throat, overwhelming the mare with the taste and smell of Sweetie's borrowed musk. “That's right. Goood cum-toilet!”

Relieved that her partner seemed satisfied, Fluttershy gathered herself, ignoring the worthlessness she felt, her sudden dirtiness, and tried to make the best of it, moving her hoof between her stifles to bring herself a little pleasure as well.

“Don't you dare touch yourself,” the little filly commanded. “You don't deserve it yet, bed-wetter.”

Fluttershy's hoof froze before it reached her private part, and she whimpered against the filly's cunt.

“Ohhh~ yehh!” Sweetie groaned at the vibration and the sound of the innocent mare's distress. “Cry some more.”

Only a second passed, and Fluttershy barely processed Sweetie's demand before she felt a hard kick to her head again from Sweetie's back hoof. She didn't hold back anymore. Her tongue grew stiff inside of Sweetie, unable to wiggle as she tensed, and she sobbed, muffled, into Sweetie's muff. Tears streamed from her eyes and she wailed and coughed unflatteringly against Sweetie's privates. Why is she... why did I ever want to do this to her?!

High from Fluttershy's emotional pain, with the help of the bigger pony's vocal vibrations, and in spite of the submissive adult foal's faltering lips and tongue, Sweetie tensed and ground into the mare's open mouth for several minutes. Against Fluttershy's sore lips and muzzle, finally, Sweetie felt herself start to spasm. “Oohhh! Yesss! Yeh—” Sweetie's noises devolved into high-pitched growls and squeals of ecstasy, and, for half a minute, she squirmed and gushed intermittently over her receptacle's relatively pure mouth. Fluttershy choked and struggled to move her mouth away just enough to cough freely and gasp for breath as Sweetie Belle rode out her finish, coating her reluctant muzzle with cum.

Panting, Sweetie Belle frowned, and her eyes sparkled at Fluttershy's distress, but she held her position. As Fluttershy wailed once more beneath her, Sweetie Belle steeled herself and kicked her fillyfriend again in the tender spot on her chin from the last strike. “Shut up again. I need to drop a doozie I've been saving.”

Fluttershy gasped. In her normal mind, she knew she'd thought about inviting Sweetie to scat play before, but she would never have forced it on her, never done what she thought she was preparing to do right now. She wasn't ready, not with the mind and feelings of an unspoiled, prepubescent foal. “Please, no! Please!”

“Open up, or so help me...” rage and self-loathing that Fluttershy remembered having journaled and suppressed for years seethed from each clenched word out of Sweetie's mouth.

“What—what did I do wroooohhng?!” she cried. Why was she being punished this way?

“I'll tell you after you swallow. Don't make me kick you again.” Sweetie kicked Fluttershy anyway in the jaw opposite the one she'd already targeted, and Fluttershy yelped.

It wasn't worth it, thought Fluttershy. Clearly, Sweetie Belle couldn't handle her urges the way that she herself had all these years. The transfer must not have included self-control. “No!” Fluttershy protested angrily. “I'm going to tell Twilight and change us back!” She may have been more vulnerable mentally, but Fluttershy was still bigger than the filly. She pushed her rump away from her muzzle abruptly, and reminded herself of her strength just in time to prevent the filly from falling off the bed.

Fluttershy began to roll off her bed. “I'll leave you,” Sweetie Belle's voice trembled, half-whispering, half-growling. Fluttershy froze again. “Do it, or I swear, once we've changed back, I'll break our engagement.”

Fluttershy's heart iced suddenly, and she reeled at the emotional blow. For more than a minute she tried to regain her bearings, but, even after her world stopped spinning, she felt clueless as to what she ought to do. Another minute passed before, mechanically, Fluttershy lay back in her previous position and she opened her aching mouth to become the filly's toilet. Too shocked to notice that Sweetie Belle's face streaked silently with tears, Fluttershy only stared off into space, hoping for it to be over soon.

Sweetie Belle returned to straddle her muzzle again, this time facing Fluttershy's wide-eyed, teary stare.

Here it comes. Fluttershy cringed in anticipation despite her best effort to show and feel nothing.

“You want this,” Sweetie Belle's calm statement drew Fluttershy's attention, and she finally noticed the remorse etched strangely in the filly's features and the wet streaks made where her tears still flowed.

Fluttershy looked bemused and afraid up into the filly's teal eyes for a tense moment without answering.

Sweetie grit her teeth. “You'd sooner become my outhouse than let me leave you!” Sweetie Belle snarled and raised her front hoof to smack the mare.

Fluttershy flinched and waited, but, when the blow never fell, she opened her eyes again to see the enraged filly, still waiting for her answer. Fluttershy nodded shakily, and the foal's hoof twitched, causing Fluttershy to flinch again. When again the strike never came, she opened her eyes once more.

“And don't you ever forget it.” The mature filly's rage melted suddenly, her weight shifted, and she got off of the abused mare. She breathed deeply and exhaled once to steady herself as she lay next to the grateful yet bewildered foalish mare. Still afraid, Fluttershy only shot quick, sideways glances at the filly.

“Today...” Sweetie Belle spoke softly and sadly to her distraught victim, “I learned that you're afraid I wouldn't want you if I knew your darkest fantasies.” Tears rolled sideways down Sweetie's face and fell softly on the bed between them. “You've been so afraid... I felt so afraid today, that I realized... there was a chance that I—that you might leave me before I even had a chance to know.”

Fluttershy understood suddenly, and her tension eased, but only a little. She turned her head to look next to her at the filly.

“Maybe, whether or not you realized it, you hoped our swap would let me know.”

Fluttershy's tears returned, and she sniffled and nodded. “I'm sorry... I didn't know how to tell you.”

Ever so gently, Sweetie Belle traced the reddened areas of Fluttershy's face, almost without touching, tickling her coat and gently soothing the pony. “Remember, please!—” the filly fought back her tears “—remember the proof I just gave you.” The filly swallowed hard and drew a shuddering breath to finish her plea. “Remember how desperately you'd rather have accepted everything just now than have nothing. When we change back, there's nothing in you that I'll abandon... unless we abandon it together.” Tears flowed more abundantly from Sweetie Belle's face, and her lower lip trembled before she bit it.

Fluttershy threw her foreleg around the filly to pull her in abruptly for an embrace and then lose herself in bittersweet wailing. Sweetie allowed herself to reciprocate, to sob aloud softly, finally, and, against the habit she'd borrowed from Fluttershy to always hold back, she squeezed with every ounce of her little filly strength.

The two clung to one another for a long time that didn't feel long at all, until dusk turned to darkness and, finally, their tears slowed and stopped.

Sweetie Belle shifted and shrugged, and Fluttershy let the filly free of her warm embrace. Wordlessly, the filly kissed the mare's bruised chin and jaw lightly. She kissed her lips, stroking her cheek softly, and trailed her small snout down Fluttershy's much larger neck and barrel. The filly trailed lower until she reached the mare's teats. They seemed to have shrunk, almost flattened, she noticed, but Fluttershy still moaned at the sensation of Sweetie's warm breath and hot mouth as she suckled them.

Fluttershy's transferred hormones and sexual wiring drove Sweetie Belle wild, and she realized how much more she preferred gentle foreplay to the educational torture she'd just put her fillyfriend through. The thought was comforting and one she knew she'd hold onto when they changed back, for reassurance that she'd probably never go through the same rough treatment she'd delivered... unless she asked for it down the road.

Fluttershy hummed and moaned happily, forgetting her previous trauma. To be like a filly again, though she knew her past—to be so sensitive and unconditioned reminded her of what she'd missed for so many years, the heightened thrill of the most simple caress, and yet it was even more than she'd experienced in her foalhood, having never had somepony older, much less somepony willing to weather the storm of such a taboo commitment. But then, few ponies ever had the care and understanding of either a princess or a foal's guardian for such a relationship. It seemed unbelievable that Fluttershy had somehow found both. She normally felt unworthy. In Sweetie's state of mind, however, she felt so much more: loved, protected, not worthless as she'd felt occasionally throughout that day in the filly's young horseshoes. She felt treasured above all else.

The littler pony gently traced with her hoof around one undeveloped teat while she suckled and played warmly with the other between her lips with her tongue. With the exchange of each other's muscle memory, Fluttershy was treated for once to an experienced tongue, lips, and hooves. Though she couldn't remember having been treated so skillfully before, her body knew and anticipated what was coming, and she spread herself to grant the skilled foal easier access to her delicate middle.

The mare's underdeveloped labia were a little red, but Sweetie Belle had drawn on Fluttershy's senses in order to avoid any real damage earlier with her hoof. Now, leaving the mare's teats, Sweetie adjusted herself to lay gently over Fluttershy's tail where her cream-colored hooves and muzzle found easy access between Fluttershy's back legs. The pony's bald mons was softer than she ever remembered, the scent, for once, was fainter than her own currently, and she quickly came to realize why Fluttershy seemed so obsessed with her filly bits on any normal day. She'd already been told, but now she knew that being so young really did make her more attractive to her mare.

Sweetie didn't dwell quite as long as she wanted to on the sight and smell. Normally, she knew, Fluttershy enjoyed that part, and she tolerated it despite always feeling self-conscious. The desire had transferred to Sweetie, but, she felt, she owed it to both of them, tonight, to give the immature mare what she remembered she loved best.

Sweetie's tongue assaulted Fluttershy's clit wetly, hotly. Fluttershy moaned loudly, ecstatically. The regressed pegasus recalled lost memories of her own masturbatory escapades, before she'd gotten bored of the usual, when simple and straightforward were more than enough. Immediate pleasure was everything she wanted, and the wise filly gave it to her as her muzzle labored on her prepubescent mare pussy.

A quick finish wasn't what Sweetie had in mind, however. When a minute had passed, the filly left Fluttershy's clit behind to visit beneath. Fluttershy let out an almost frustrated moan, missing the texture of Sweetie's tongue on her hottest spot, but rocked by new waves of stimulation as her lover's tongue stroked once sensually along her labia, then rapidly, moving from outer lip to outer lip, then just inside, against the inner-edge of one, spreading it outward, then against the other.

Sweetie's tongue dipped, licked, spread, and lapped at the mild, intoxicating flavor of Fluttershy's tender filly parts, and she moaned, swallowing for half a second before returning to the mare's regressed, swollen clit. As another minute passed, Sweetie's switching between Fluttershy's pink parts became more rapid until, unable to resist any longer, Sweetie focused her oral ministration on her marefriend's nub.

Fluttershy squeaked and sang her appreciation at the filly's slick tongue massaging and rolling against her favorite body part. To her added pleasure, the tip of Sweetie Belle's small hoof played momentarily at her entrance, prodding lightly as Fluttershy's tension built. It would have been plenty to be brought to finish quickly, but Sweetie Belle had made sure Fluttershy's tension built gradually. The mare's whole body trembled for release, and finally, as Sweetie Belle slid her hoof inside of the mare's tight tunnel to begin thrusting and took her clitoris firmly between her lips to flick and press at it with her tongue, Fluttershy felt her pleasure ascend beyond any single orgasm she could remember, and her walls began to contract like a heartbeat against the fullness of Sweetie's invading hoof.

Seconds into Fluttershy's first orgasm, Sweetie's passionate tongue-massage persisted, Fluttershy trembled again, and, again, still wracked with indescribable pleasure, she came. Parts of her lower body that had only remained tense, began to pulse together with her already rhythmic vagina and anus, and as a third simultaneous orgasm struck, the tension in Fluttershy's eyes was overwhelmed by her own shock. As every muscle in the pegasus's pelvis and lower back pulsed in rhapsodic pleasure with her genitals, she stared wide-eyed and open-mouthed upward, squeaking moans stopped, caught for a second as if by surprise, before they rang from her once more, frightening half of the animals in the cottage.

As Fluttershy's screams died, Sweetie's mouth and thrusting hoof slowed, and she sighed through her nostrils, happy she'd made up for her fillyfriend's maltreatment before. Sweetie's lips and hoof left the thoroughly pleasured parts of her lover with a soft sucking noise, leaving the immature mare's pussy to dribble down across the dock of her own tail and onto the bed. While normally Sweetie thought the wet spot on the bed was annoying, she smiled and took quiet pleasure at it now. Fluttershy was too exhausted to care either way.

As the filly returned again to her mare's side, it was all Fluttershy could do to thank her. “I—I love you, Sweetheart.”

“And I'll love you forever.” Sweetie's reply was emotional. What she'd lacked in innocence that day, she felt she'd more than made up for in how intensely she loved her partner. That night, Sweetie knew, though she'd never have guessed it before, she'd always been loved more by Fluttershy than she had loved Fluttershy herself. She determined, then, to change that after they returned to normal.

The two shared gentle kisses and prolonged nuzzles a while longer, before Fluttershy yawned. Moving to pull the covers up over both of them, Sweetie caught her yawn as well. In each other's hooves, they drifted off to sleep.

Author's Note

Written because fans of Flutterbelle deserve something for their patience while I continue to work on side projects instead of Fallen Angels and because I really liked this idea when I thought of it for the Padded Ponies collab recently.

Sources:
http://www.human-memory.net/types.html