Rainbow hopped up and spun around in a quick blur; she always had to be the fastest, of course, but this time she had been given extra motivation. Laying down on Shining's half-and-half-colored belly, she slid back a little, pushing her tight, muscular little rump up at me and lewdly lifting her tail. Between those toned cheeks, her thin slit of a marehood winked up at me greedily.

I watched, biting my lip slightly, as a thin dribble of Rainbow's lubrication dribbled down to mingle with the thick stallion cum leaking out of the lavender marehood below it. It was enough to send a jolt of stiffness through the phallus I'd borrowed from my brother – it twitched, begging to be rammed into her.

I took my time and enjoyed the sensations, though, or at least I meant to. Leaning forward, I aligned my new equipment perfectly and kissed the tip against Rainbow's steamy nether lips. Goddess, the heat coming from her was incredible!

Still slippery from my brother's tongue, Rainbow's marehood was able to glide easily across the wide, flared tip as she winked repeatedly. “What are you waiting for, Twi? Give it to me!”

How could I ignore a request like that? Easily. “Not until you beg for it,” I whispered. It was so much fun teasing Rainbow.

“Screw that!” Rainbow jolted herself backward. Her thin nether lips spread wide and enveloped my tip, swallowing it easily and sliding down my already-slick shaft.

I gasped, unable to react in time to keep Rainbow waiting.

After a lusty grunt of her own, Rainbow looked back over her shoulder and grinned at me. Her marehood winked around the top of my shaft, rippling around it. “You don't mess with the Dash,” she said, following it with a laugh I could feel through my penis.

I grinned back at her... and then I jammed my brother's entire length inside her in one massive thrust.

Rainbow's laugh trailed off into a high pitched, almost bat-like, squeal. She collapsed down onto Shining, quivering and struggling just to breathe.

Her warmth, the incredible heat of her, surrounded me, pressing me on all sides inside her. I leaned down and whispered into her ear: “Better?”

She could only moan. I felt her entrance winking against the rim of my sheath. Her entire marehood convulsed around my immovable shaft. No way... there was no way she could be that fast, be that much on a hair-trigger. She couldn't already be close to—

Rainbow screamed right into my brother's ear, and the muscles inside her clenched down on me so hard I wouldn’t have been able to move. Hot juices sprayed against my sheath and balls as she clenched against my hardness again and again. She kept on, juddering as wave after wave of convulsions pulsed through her... until, finally, her legs gave out and she collapsed down on my brother, panting into the crook of his neck.

“Wow, Rainbow,” Shining said, “Twiley wasn't kidding when she said you were fast.”

She looked away from him and blushed. “It was just so...”

“Big?” I prompted.

“No...” She shook her head. “So hard, so... I dunno... insistent, primal?”

I grinned and moved my still-hard stallionhood slightly inside her, earning a squeal. “And it's not over yet.”

She whimpered slightly and melted around my ardent length.

Now, now that I'd sated her wild side, I could take it slow. Running my hooves along her heaving sides, I felt the long, lean muscles there. Underneath the softness of her coat, she was hard and solid and smooth. I pulled out of her slightly, feeling her nether lips rubbing against the sides of my shaft, trying to hold me in. And yet, inside her, beyond that clenching, winking boundary, she was soft as pegasus pudding. How could she be so firm on the outside and so plush and inviting on the inside? Even after all the times I'd messed around with Rainbow, I'd never been able to feel her literal softer side before. What a difference having a penis makes!

I rammed into her again, expecting the same squeal, but it didn't come. Instead, she just gave a low moan.

Goddess, she felt good wrapped around my shaft. With every thrust, I could feel her tight lips against me on the outside and the irresistible plush warmth of her insides. She was amazing, incredible! How could I have been missing out on feeling this my whole life?

“Oh Twiley!” Shining's grunt from below surprised me. “Keep doing that! I can feel you through her belly. I can feel your dick inside her!”

I grinned and changed my angle, pushing down more, earning moans from Rainbow and Shining.

Rainbow came again... and again... and again. One orgasm came on the heels of another, and I just kept thrusting through it all, getting closer myself every time she clenched around me, squeezing me so hard I could barely slide against the pressure of her inner walls. She and Shining started kissing, making out with an enviable intensity even as each orgasm rocked through her body.

She must have felt me flaring up inside her. “No! I—” she moaned loudly “—I can't get pregnant. Pull it out!” Shining shut her up with a heavy kiss, but it was too late. I couldn't ignore a request like that and live with myself afterward.

I winced. By this point, I wanted nothing more than to fill her pussy with my brother's cum. Luckily, I had a pretty good alternative.

Sliding out of Rainbow in one long, fluid motion, I popped free from her clenching pink marehood and aimed just a bit lower... The flared head of my stallionhood butted up against the dripping lavender vulva below, the wide tip of it simply pressing against the his lips. With enough pressure, though, it spread those lips wide and pushed inside, spreading Rainbow's juices as it went.

Shining gasped as his borrowed marehood was filled to the brim, forced to wrap around the round girth of it.

I was cumming before I even finished my thrust. Thick white spurts shot out into my own marehood on another's body, splashing out into the void inside even as I pushed deeper and deeper. By the end of the first wave, I'd fully hilted myself inside, and the pulses that followed surged straight into my own womb, deep inside Shining's body.

I emptied my borrowed testicles into my marehood shamelessly, letting it pour out around the edges in prolific splatters of mixed juices, pressing my trembling body into it as hard as I could, even as the spurts gradually died down to little twitches, and then nothing.

For a moment, we all laid panting. I could feel Shining pulsing my pussy around the still-warm stallionhood inside it. Rainbow looked back at me with a big, dumb, satisfied grin on her face.

“So,” Shining said, after we'd all caught our breaths for a moment, “about that promise...”

I pulled out of him slowly, watching the shiny-slick stallionhood slide out and eventually pop free, spilling a deluge of white when it came out and swung free. “He's right, Rainbow.” I hopped back off of them and stood next to the bed. “We've been neglecting him.”

Rainbow rose up a little higher, then leaned back down to give him a little peck on the muzzle. Then she took wing and darted around to land right next to me. “I think he's earned it... But it does look a little...”

“Messy?” I asked.

Rainbow looked at the sloppy marehood in front of us again. She nodded.

I smirked at her, stepped forward, and thrust my face into the middle of it, rubbing the steamy white mess all over my face as I nuzzled into that lavender crotch. When Rainbow gasped, I pulled back away with lots of sticky strands still connecting me to my own cum-filled marehood, and I grinned at Rainbow through the mess. “Come on in,” I cooed, “It's delicious.”

Rainbow stammered, but she took a couple small steps forward.

“Plenty of room for two.” I pushed Shining's lavender legs open wider.

She took a deep breath, almost as if she was about to make a deep dive into the ocean, and then she darted in next to me, kissing me full on my sloppy lips.

A few strands still connected us when we separated, and the two of us shared a sultry look between each other.

And then we gave Shining what he so richly deserved.

We both plunged down to his marehood and licked up each side of it, our tongues darting back and forth across the slit in between those plush lips. Shining's groans only spurred us on.

Slick nectar and cream coated his silky-smooth nether skin, from his borrowed marehood, from Rainbow's, and most of all, from his own phallus when I'd twice sprayed the full load of his testes inside. We devoured it all, Rainbow and I, greedily licking and slurping both his lips and each other's.

Of course, we gave each other less and less attention as Shining's body tensed, as his breathing quickened, as he squeezed his soft lavender thighs together to push us in deeper. I went low, flicking my tongue deep inside my own insatiable marehood, greedily licking up the endless trickle of salty-sweet juices it gave me. Rainbow opted for the high road, latching her lips onto the upper tip of the jutting purple vulva and sucking gently. I could see her mouth moving just above me, the way her cheeks bulged in and out as her tongue worked feverishly against Shining's clit.

Shining squealed. This was no masculine grunt – it was the cry of a mare who had been completely overwhelmed.

But soon, I was overwhelmed. The precious trickle I'd been lapping at became a flood, pouring out of his mare-form depths straight into my open mouth and down my throat. The whole mixture, the sexual fluids from all three of us, flowed into me at an astonishing rate. I swallowed as fast as I could, but by the time the flow ended, I was still left with my mouth full and the milky-white ambrosia dribbling from the corners of my lips.

As we both pulled away, Rainbow caught my eyes. Hers went half-lidded. Mine went wide.

She kissed me, splashing my mouthful of our juices across her face, plunging her tongue deep inside my still-full mouth. She lowered herself, forcing me to turn my head down, and her tongue forced my lips apart.

It flooded into Rainbow's mouth, sloshing around her tongue. She kept it there only long enough to look Shining in the eyes and swallow deeply. Impossibly, his face grew even more flushed as she opened her mouth wide again and showed him her squeaky-clean tongue.

Shining raised himself up to a sitting position, smearing even more wetness into the edge of the bedsheets. “Wow, girls. That was incredible! I've never felt anything like it before.”

I grinned and looked down. My brother's penis was completely erect again. How much of that was his own libido? How much of that was from how much arousal I was feeling?How much of that was from seeing Rainbow obscenely swallowing the mix of all our juices? It twitched, letting me know on no uncertain terms: it wanted to be thrust into something again. Who cared what I shoved it into, just as long as it found a home inside something warm and wet.

I glanced from my phallus, up to Rainbow, back down, back up at her. “So, what's next?” I asked with a twinkle in my eye.

Rainbow paused for a moment, in uncharacteristically deep thought. Then she grinned like a foal who'd just gotten away with stealing every cookie in the jar. “Give me your tail end, Twi. I want to feel what you feel when you're getting banged by your brother!”

I grinned, ready to give her exactly what she asked for. She had no idea what I was planning.

Author's Note

This story is brought to you thanks in part to my Patreon supporters! They're invaluable for keeping me focused and motivated to write with the power of the deadline.

If you'd like to help keep me writing, please check out my Patreon page.