Sweetie Belle propped herself up to a sitting position, though her hind legs were still splayed out in front of her, putting everything she had on full display for Rainbow Dash. “But...” She gave a little sniffle and her best teary-eyed look. “But we're not done yet, are we?”

“You're insatiable, aren't you?” Rainbow shook her head, grinning down at her. “But come on – let's get cleaned up. I'm pretty sure you know whether you like mares or not by now. And as fun as you are to play around with, I really shouldn't be doing this kind of thing with a little filly.”

Sweetie Belle didn't let up with the sad puppy eyes. She knew Rainbow would give in if she just tried a little harder. “Aw... But we haven't even gotten to try this yet!” Using her rudimentary magic skills, she opened the box underneath her bed and levitated her strap-on up where Rainbow could see it.

Rainbow's eyes went wide. Her jaw dropped.

It was quite a sight, Sweetie Belle had to admit. The straps on its base were adjusted nice and tight to fit her small body perfectly, but the size of the dildo itself would be enough to make a full-grown stallion blush. Its rubbery length was molded in perfect detail, with all the veins and ridges of a real stallion's cock, but what probably shocked Rainbow the most was its coloring: rainbow stripes around its girth all the way up and down.

“Woah.” Rainbow pointed at it, quite unnecessarily. “Where'd you get that?”

Sweetie Belle shrugged. “I, um... I found it somewhere.” Rainbow didn't need to know precisely where she'd found it, she decided as she lowered it onto her own crotch and cinched the straps around her hind legs. This magnificent specimen of a strap-on had come from the one time when all three of the Cutie Mark Crusaders had dressed up in one tall trench coat and snuck into a sex toy shop. She couldn't deny thinking of Rainbow Dash when she'd picked out this one ... and she wondered what Rainbow would think if she knew Scootaloo had a matching one. With a little zipping sound, she pulled the last strap nice and tight.

Rainbow stared at her confusedly for a moment, then suddenly recoiled, her gaze growing accusatory and harsh. “Hey! You've been playing me all along!”

Standing up on the bed, Sweetie Belle came closer to Rainbow and reared up, putting her big rubber cock on full display – it was long enough that the tip of it stuck out between her forelegs! – and she looked Rainbow Dash unashamedly in the eye. “Yeah, and...?”

For a moment, Rainbow did nothing. Oh no – had she blown it? Had she come on too strong? Maybe Rainbow didn't like penetration? But then Rainbow let out a little laugh ... and she turned around, lifting her tail for Sweetie Belle. “Kid, you're my kind of filly.”

Yes yes yes! Oh what a view! To see Rainbow like that with her hind legs spread and her tail raised, just begging to be mounted ... it made Sweetie Belle's legs go so weak that she nearly collapsed back down onto the bed. The curves of Rainbow's tight and toned ass cheeks, the arc of her rainbow tail, and the gooey pink flashes of her pussy winking open would return over and over again to spice up Sweetie Belle's dreams for years to come.

For now, though, it was time for her to mount her mare.

But that turned out to be a lot more difficult than Sweetie Belle was expecting. Playing around with other fillies was one thing, but Rainbow was, well, taller. Sweetie Belle's hooves scrambled up against Rainbow's rump just above her tail, and she jerked her hips upward, trying to plant the tip of her strap-on against Rainbow's pussy, but she just couldn't quite do it – she couldn’t reach high enough.

It wasn't until Rainbow bent her hind legs, squatting down a little bit, that Sweetie Belle was finally able to reach the all-important spot she'd been trying for.

Rainbow moaned girlishly as Sweetie Belle pressed the tip of her rubber cock right up against those perfect blue pussy lips. Sweetie Belle looked down at what she was doing, savoring the view. Her strap-on's purple tip pushed slightly inward, spreading Rainbow's pussy lips slowly apart before it finally sank in. Then there was the blue stripe just below that. Rainbow moaned again as it glided between her pussy lips, pushing deeper.

After that was a green stripe, yellow, orange, red, and purple again. Sweetie Belle licked her lips as she watched it slowly disappear into the very pony who'd inspired her to buy it in the first place. She could only feel it by the pressure its base put against her underbelly and teats, but it seemed to be sliding in so smoothly and easily, as if Rainbow's body was welcoming it, almost even pulling it in.

By the end, she lost control of herself, shoving the rest of it in quickly and harshly, earning a startled cry from Rainbow Dash. But that cry quickly faded into a deeply contented moan. Rainbow pushed her ass up and back toward Sweetie Belle, almost lifting her up as she shifted slightly from side to side. “Mmyeah...” Rainbow's wings fluttered against Sweetie Belle's forehooves. “That's nice...”

Standing on the very tips of her hind hooves, Sweetie Belle strained to rock back and forth a little. She could barely get enough traction against the soft bedspread. But she did manage to slide the strap-on in and out of Rainbow's pussy a little. The way she could feel Rainbow's flanks trembling as she did so made warmth bloom inside Sweetie Belle almost as intensely as if she'd been using a real cock.

Once Rainbow got control of herself back and lowered her ass back down a little, Sweetie Belle could really start thrusting inside her. She started off slow, though, gazing lovingly down between Rainbow's ass cheeks at the way her pussy lips stretched in and out as the rainbow stripes of rubber cock slid past them. Sweetie Belle could even feel it when Rainbow's pussy squeezed around her shaft – that made the base of it tilt slightly, pushing against her tiny filly teats.

Soon, though, Rainbow groaned needily. It seemed she'd had enough of the tender, gentle kind of loving. “Come on, kid,” she said. “I know you can do better than that. Give it to me!”

Biting her lips slightly, Sweetie Belle scooted forward a little, clenching her forehooves tightly around Rainbow's waist ... and she did give it to her.

The little muffled claps of Sweetie Belle's thighs hitting Rainbow's ass cheeks mixed with the squishy wet sound of the dildo's veins rippling through Rainbow's entrance to fill the room with a lewd background rhythm to match the little gasps Rainbow made every time Sweetie Belle bottomed out inside her. This was hard work! She was actually starting to build up a sweat already, but she just kept going and going because those delicate little sounds Rainbow made were just so delicious. Who would have thought that big, tough Rainbow Dash could sound so girly and soft?

Not that Rainbow was completely submissive and melty – even as Sweetie Belle really got into it, Rainbow looked back over her shoulder at the filly and smiled with a challenging look in her eye. “Is that all you've got? Come on, kid – fuck me like you mean it!”

But ... she had been! She'd been pounding it into Rainbow almost as hard as she could! But this was Rainbow Dash – almost wouldn't cut it. Sweetie Belle grit her teeth and slammed the strap-on as hard as she could into Rainbow's pussy.

Rainbow rocked forward under the sudden blow, dropping the front of her body down onto the same pillow she'd been sitting – and leaking – on a moment ago, leaving nothing but her rump sticking up for Sweetie Belle to hump against.

This time, Sweetie Belle really did give it everything she could. Her forehooves dug into Rainbow's sleek, firm sides as she thrust with all her little filly might. She was already starting to feel the strain of it in the muscles of her hind legs and ass, but she kept at it. Each thrust pulled the strap-on almost all the way out of Rainbow before shoving it savagely back into her slick, ready pussy. This wasn't like playing around with other fillies – Rainbow was a full-grown mare and could eagerly take anything Sweetie Belle could dish out.

And even that wasn't enough. Rainbow's gasping breaths grew more and more desperate. Without even lifting her face from the pillow, she shouted, “More! Harder!”

Sweetie Belle couldn't keep up. She was already giving Rainbow every last bit of her energy – she could barely keep going like this as it was. But she wasn't giving up that easily. No matter what, she'd keep going as hard and fast as she possibly could, all the way until she dropped!

Even though Sweetie Belle couldn't manage to do it any harder than she already was, in the end, it turned out to be enough. Just as Sweetie Belle hit the last desperate reserves of her energy, Rainbow tightened up, making it even harder to thrust into her. Sweetie Belle ended up stuck all the way inside, with not enough energy in her trembling body for even one more thrust.

That seemed to be just what Rainbow needed, though. Her pussy gave a couple powerful squeezes around the rubber cock so deep inside her, and then she finally came. It was the long, drawn-out moan that finally clued Sweetie Belle in to what was happening ... and then the rhythmic pulsing of the strap-on's base against her teats and the repeated heaving of Rainbow's sides made perfect sense. With renewed vigor, Sweetie Belle shoved her hips forward, plowing the strap-on as deeply as it possibly possibly could go inside Rainbow Dash.

That seemed to start Rainbow's orgasm all over again. She cried out loudly against the pillow, grabbing it with her forelegs and clutching it tightly around her chest. Her wings fanned out and trembled, every bit as stiff as the rest of her body. A little bit of warm marecum even spattered out against Sweetie Belle's inner thighs.

When Rainbow finally collapsed, Sweetie Belle did as well. All the colors of the rainbow suddenly appeared in quick succession as the big rubber cock slipped out from Rainbow's pussy. The moment Sweetie Belle flopped backward onto the bed, it came and smacked wetly down on her chest.

Rainbow hadn't fared much better. She'd collapsed over sideways and was perfectly still except for the way her sides rose and fell with deep breaths and the way the base of her tail twitched from time to time. Milky-clear juices dribbled sideways out of her well-used pussy.

For a few moments, Sweetie Belle fumbled with the straps around her legs, but she was just too tired and shaky. She gave up quickly ... and she wasn't about to try to use magic when she was this exhausted. That would never end well. Between her deep, panting breaths, she moaned contentedly. “Rainbow...”

Rainbow lifted her head up. “Uh-huh?”

“You are the greatest foalsitter in the history of foalsitters!”

Shaking herself a little, Rainbow got up and came over to Sweetie Belle. She nudged her face in around Sweetie Belle's hips, nuzzling her nose along the sensitive fur of Sweetie Belle's thighs as she made surprisingly quick work of the strap-on's buckles with her dextrous lips. Once it was free she held its glistening length up in her hooves, smirking down at Sweetie Belle. “Oh no you don't – we're not done here yet!”

Author's Note

This story is a commission for Starless. If you'd like to get a commission of your own done, go to my Commissions Page for all the details you need. And remember, Patreon supporters get big discounts on commissions!