She needs cock like a mare dying of thirst needs water.

The look on Twilight Sparkle's face when his cock was freed, springing up and nearly bumping into her cheek, was everything.

"H-... H-... Howww...?" Twilight breathed, her eyes zeroed-in on his twitching, throbbing, bobbing third leg as it broke her mind. She reached out and wrapped her hands just beneath the head, groaning as she felt its warmth and weight in her hands, confirming that this was no dream, that this was real. "I-I measured you when you first arrived... You were only five and fifteen-sixteenths inches! Did Celestia cast a spell, or...?"

Isaac chuckled, groaning in lust at how infatuated the bookish alicorn was with his dick. "It's been steadily growing day by day from the moment I got here, it seems. Something about the ambient magic of this world is agreeing with me."

"Wh-What?!" That got Twilight's urgent attention immediately, finally tearing her eyes away from his dick to look up at his face. "But you were a magically inert being when you arrived! If you're becoming magical, that can have a whole host of knock-on effects! We should run some more tests to see-"

Isaac put up his hands. "Woah woah woah! You can just let me worry about my body and magic, right? For you, in this moment, getting fucked by my cock is far more important, right?" He didn't want Twilight going on a tangent and leaving him blue-balled. (And he definitely didn't want Twilight accidentally discovering the Root of Honesty within him, if that was even possible!)

Thankfully, Twilight **** out a sigh from her lungs and returned to making lovey-dovey eyes at his cock and giving it double-fisted strokes. "Y-You're right, sorry. It's just... so fascinating! This is such an impossible and momentous occasion...! A true male with a real shot at becoming the Harem Master we all need... so badly...!" The more she spoke, the more strained she sounded, the faster her hands rubbed him.

Then she stopped, lowering her hands to her thighs and looking down. Isaac was confused, not to mention left hanging. "Uh, you okay, Twilight?" he asked, not realizing he was asking a basic question. Thankfully it was an inconsequential one.

The alicorn mare took a deep breath to steel herself and looked up at him with pleading, shimmering eyes. "Isaac- No, Master...! I know it's your right to do whatever you want with me, and I'll gladly satisfy every one of your desires, whenever and wherever...!"

That was more like it. Isaac had plenty of ideas of how to play with the Princess of Friendship and Element of Magic. "Yeah, you've been training all your adult life for this, learning and inventing all sorts of special magic to satisfy all sorts of kinks, right?"

Not a whole lot changed with that question, except that Twilight's posture became a little less **** and just the slightest bit more self-assured. "I-I have, Master. Whatever you and your dick desires, I can probably make it happen with my magic. But..."

"But?" Isaac echoed with a raised eyebrow.

"But - sorry for my imposition - I need something first," Twilight admitted at last. Then she reached out, grabbed his dick, and cast a spell that bathed them both in purple light.

Isaac felt tingly all over for an intense second, and then the light faded. He realized after a moment that they had teleported... into Twilight's bedroom, elsewhere in the palace. His clothes had been completely removed, folded up and piled neatly on one of the dressers. And Twilight was no longer on her knees before him, but rather...

Twilight was laying on her bed, on her back, facing him upside-down with her head hanging just off the edge of the sheets. Her hastily assembled clothes were completely discarded, showing off her huge purple breasts splaying to either side, plus her wide hips, thick thighs, bare swollen pussy... There was a lot to appreciate, but it was also clear that the focus was on Twilight's mouth.

Staring at his cock upside-down, Twilight held her mouth open in a big 'O' for a moment, licking her lips, before addressing him again. "Please, Master... I need your cock in my mouth. In my throat. I want you to just... use my mouth like a pussy. I need you to be rough, stuff me full, smack my face with your balls, and don't stop until you bloat me with cum. I-I'll do anything you want after, but... I've been fantasizing about this moment forever, so... please?"

The last thing he'd expected from this encounter was for Twilight to kind of take charge, but Isaac wasn't necessarily complaining! And he'd given all the alicorns oral fixations earlier, right? That question must have hit Twilight the hardest of all.

With a confident strut, Isaac strode the few feet separating his cock from Twilight's mouth, pushing down on the base gently so that it'd line up. When the head was just in front of her lips, she puckered up and gave it a kiss, then licked all around the head, moaning at the flavor on her tongue. "Ungh, Isaac, your cock is... magnificent...!"

It looked like it wouldn't fit, even though Isaac knew that it would. His cock was thick, probably thicker than Twilight's neck. She'd stretch, for sure, but given how new he was to all of this, Isaac had a moment of trepidation anyway. "So, uh... If you're running low on air..."

"Isaac, I will teleport oxygen into my lungs and teleport carbon dioxide out if need be," Twilight half-growled in an unexpected moment of intense sternness. "Now face-fuck me!!"

Well, shit, no arguing with that! Isaac pushed his hips forward, his cockhead sliding past her lips and slipping into her equine muzzle. Her tongue blazed a trail across his shaft immediately, licking every square inch of surface area she hadn't tasted yet as it slid by. She moaned into his shaft, making him feel her voice reverberating through his flesh, and then it abruptly halted as his cock poked into her throat. True to the question he'd asked earlier, though, her throating skills were naturally expert, and she didn't put up a fuss as his gigantic neck-stretching cock continued its journey.

Isaac could see the bulge of his head and shaft pushing down her body, wearing her esophagus like a condom. And just as he wondered how it felt through her body, Twilight reached up and started stroking his cock through her skin with her hands while she swallowed around his cock, somehow deepthroating him and jerking him off at the same time! Twilight wasn't as big as her alicorn peers, not as effortlessly able to swallow his cock like Celestia could with her extra size, but it was clear she was willing to use her whole body to make up for it!

It was slow going, if only because Isaac was instinctively trying to be careful on the first thrust. Somehow they were close to the hilt with no problems so far, and his cock seemed to be nearly at her stomach by now. Isaac tried not to think about how any of that was possible or safe... but he was now in reach of Twilight's huge tits, so he quickly found a distraction. Fucking Twilight's throat and palming her massive, perky, firm alicorn breasts, playing with her thick, juicy nipples... Damn if it wasn't good to be the Master! Twilight seemed to be enjoying it, too, judging from the way her legs writhed, sliding and kicking around the upper end of the bed.

Then, finally, her nose bumped into the cleft between the base of his cock and his swollen, heavy balls. His sack smooshed over her face, covering her eyes. Her mouth was stretched tightly around the base of his dick, and his entire shaft was inside her body, all the way down to her belly and then some, stretching her out a little further.

Twilight came then and there, juices spraying from her pussy and coating the pillows and the headboard of her fancy bed. She lifted her arms and wrapped them around Isaac's waist as much as she could, hugging him tighter against her body, clinging on and embracing him for dear life and love. Isaac could feel how happy and satisfied she was, how grateful she was that he'd indulged her like this, every part of her body radiant with overwhelming pleasure and joy.

Then Isaac started to pull back, dragging his cock back out of her stomach, throat, and mouth. Twilight's muffled moans vibrated around his shaft, her whole body stiffening with the feeling of his monstrous dick violating her. Isaac reared back as far as his hips would allow... and then he slammed forward, shoving his dick all the way back in and smacking her face with his crotch! A muffled squeal erupted from Twilight's body. Her legs pulled up and her pussy let out another spray of juices soaking her bedsheets.

Isaac got into an unsteady rhythm, unused to handling so much cock inside such a tight passage. Thankfully, his body seemed up to the task, giving him enough strength to speed up the way Twilight wanted until he was thrusting into her mouth like it was her pussy, while she just accepted his whole length with enough skill to shame a sword-swallower.

He could feel her horn lighting up near his balls, and a tingling magical aura surrounded his sack, rubbing and caressing them as he face-fucked her. Even with her whole body stuffed with cock, Twilight was doing everything in her power to get him off.

That realization was what tripped him over the line. Isaac could feel an enormous amount of cum building up in his body, his cock swelling even thicker in Twilight's throat. He shoved his way back in, all the way down to the hilt once more, and let out a growling howl as the floodgates opened.

There was no room in Twilight's body for cum to go, but it **** its way in anyway. Twilight's belly started to bloat up like a balloon, obscuring any sight of her spraying pussy as it swelled, wobbling with the presence of his sticky semen. Every pulse of his cock sent another pint of cum traveling down Twilight's body until it joined the small pond filling her stomach. Twilight was little more than his cock's condom at this moment, and it seemed neither of them could be happier.

When it was finally over, Isaac was still buried mostly hard in Twilight's mouth, almost too drained to pull out of her. Yet he summoned his strength through the fatigue and afterglow and started to drag his cock backward out of her mouth. His shaft was coated in saliva and, towards the lower half, leftover semen clinging to his cock and her mouth in long strands.

After what seemed like an eternity, Isaac's cockhead finally popped out of her mouth, and he actually fell back onto his ass from the sudden jolt. His cock and her mouth were dripping with excess fluids, but for the most part, Twilight seemed to be keeping all of his cum inside her. In fact, she was licking up the strands on her lips even as she caught her breath.

"Haah... Isaac... You're an excellent Master... and such a good friend~," Twilight rasped between breaths with absolute sincerity.

Isaac couldn't help it. He laughed. He laughed hard.

What kind of "friend" warped reality into their personal sex-**** paradise, anyway?