Mana transfer time!

"S-sorry, Rin," Shirou said, turning red.

"If want to do this in one move, we'll need deeper reservoir. A conjugal mana transfer."

Shirou blinked, his face a mask of confusion. "A what?"

Rider’s tongue, that incredible, prehensile muscle, snaked out to lazily collect your spend from her chin. She savored it with a soft, delighted hum. "He means we need to fuck them, Emiya."

The bluntness of it made Rin’s entire body flush a deep, crimson red. "Rider!"

"It’s the truth, is it not, mage?" Rider purred, not taking her unseen eyes off you. "Your theorom is clear. For a recharge of this magnitude, direct, internal emission is required. The most efficient way to transfer life ****." She shifted, her hips swaying with a serpentine grace as she moved to straddle your legs. "It seems our duties are not yet finished."

Rin looked like she wanted to argue, to cite some obscure paragraph that allowed for a less intimate alternative, but then your cock rose to the occasion, pressed to Rider's stomach, to her womb. The grim set of her jaw, the way her shoulders slumped in resignation, told the true story. Rider’s damaged Spirit Core was a priority. She took a steadying breath and turned to Shirou, her expression softening into something more apologetic. "She's… not wrong. For the spell to work, we need to… connect. Fully."

"Well..." Shirou smiled. "We are dating. Let's do this."

With a resolve that seemed to drain the color from her face, Rin stood. Her fingers trembled slightly as she unclasped her skirt, letting it pool at her feet. Her thin white top followed, leaving her in simple, practical underwear that she discarded with a quick, nervous flick. Her body was assfull and elegant, subtle curves and small boobs with a fat, cheeky heart-shaped ass.

Rider had a lavish, womanly abundance. She was beautiful with big boobs, childbearing hips, and also tall. It was hot.

Seeing Ri nstrip, Shirou’s breath hitched. His cock, which had softened, gave a valiant, immediate twitch at the sight of his girlfriend laid bare for the first time. A bead of pre-cum welled at his tip, oozing slowly down his modest length. It was a sweet, earnest reaction, full of his deep, longing affection for her.

Rin climbed onto the bed, positioning herself over him with a clinical focus that couldn't entirely mask her own nervous curiosity. "Just… relax, Shirou. Let me…." Her voice was a soft, reassuring murmur meant only for him. She reached between her legs, her fingers brushing against herself, and then she guided him. The moment his small, eager cockhead pressed against her entrance, she paused, taking one final, steadying breath.

Rin sank down.

It was a gentle, loving motion. He filled her, but just barely. You saw the minute flicker in her sharp aqua eyes—not pain, but a dawning, internal realization. A quiet, "Oh." It was the silent acknowledgment of a reality that didn't match the unknown fantasy. She bit her lip, a gesture meant to hold back a sigh, and began to move, a slow, tender rock of her hips.

"Here...!" The first thrust. Seeing the lack of reaction, he went harder. "Again...!"

Again and again and again, he thrust. You fucked her. You grabbed her hips and used his athletic body to get her to feel his dick.

"You’re… doing so good, Shirou," Rin whispered, the words sweet and encouraging, a lie of omission she told for the sake of his heroic heart.

Rider watched them for a beat, a look of profound disinterest on her face. Then she turned her full attention back to you, and the atmosphere shifted, electrified by her raw hunger. "Now for the main course~!"

She didn't guide you. She simply rose up on her knees, positioned the throbbing, immense head of your cock at her slick entrance, and dropped her full weight down in one devastating, claiming plunge.

The effect was instantaneous and spectacular.

A sharp, choked gasp ripped from Rider. She was Medusa, she was sultry and in-control. Yet...

"Hghgnngghhhh~!!!"

Her back arched violently, her magnificent breasts straining against nothing. Her divine pussy clenched around you, a series of rapid, uncontrollable convulsions that milked your length in a breathtaking rhythm. Her head snapped back and shriek erupted her lips as her first orgasm crashed over her without warning. "A-ah! Haaah! S-so… f-full!" she cried out, her voice cracking with the intensity of it. "S-shooo Master! So much cock! W-won't! No! C-c-cummiiing~!!!"

Tall and full of sensitive pride, that was Medusa for you. She tried to dominate and failed when she felt the full scope of your cock.

Your cock was just too good.

The Servant rode the waves of her climax, shuddering and moaning, her inner walls fluttering around you in a dizzying, addictive pulse. Slowly, she leaned forward, bracing her hands on your chest, her long purple hair cascading over you like a victory banner. A dazed, ecstatic smile spread across her face. "Gods… I knew you would feel incredible… but this…"

Her eyes. You could see them. Feel them. Burning into you and telling you she wanted more. She did it herself too. Rider began to ride you, not with Rin’s gentle rocking, but with powerful, piston-like strokes that sank you to the hilt with every descent. Each one drew another breathy gasp, another broken moan.

"Oh gosh! Oh gods! Oh gooddsss! T-this cocckk! E-even Zeus could never...!"

The room was filled with two distinct symphonies. On one side, the soft, earnest sounds of Shirou’s efforts and Rin’s gentle, whispered encouragements. "That’s it… just like that…"

On your side, it was a riot of sensation. It was fucking loud. "I'm cumming! I'm cumming! I'm cummiiiing~!!!" Rider’s cries, the slick, wet sound of your joining, the way her nails dug into your pectorals. She was a woman utterly consumed, lost in a sea of pleasure only you could provide.

Fueled by the sight of your passionate entanglement, by some misguided competitive spirit, Shirou suddenly sat up, wrapping his arms around Rin in a tight embrace. "Let’s match them, Rin!" he declared. Rin was taken aback, especially by the kiss, and then the first thrust.

"S-Shirou...!"

The kiss ended and he began to thrust upwards into her with all his athletic strength, his hips pounding against hers in a frantic, **** rhythm. Boobs to his chest, close and tight, he fucked her as best he could.

Rin gasped, more in surprise than pleasure, her eyes going wide. She held onto his shoulders, her body jostled by his enthusiastic but...

"N-not bad! K-keep going!"

"I will!"

...ultimately insufficient efforts. It was movement without profundity, friction without fire. Her lips were pressed together, her expression one of enduring patience rather than unraveling ecstasy. Shirou grunted and grunted. He looked her in the eye, thinking she was satisfied and just went harder.

Harder but not better.

Meanwhile, Rider was screaming your name. Each of your thrusts, deliberate and deep, sent another quake through her. She was cresting again, her third orgasm building with terrifying speed. "Yes! Yesss! Right there! Don’t stop! Make me cum again!"

You did that. Her legendary erotic composure was destroyed, her mythical grace replaced by primal need.

You could feel your own end approaching, a familiar, immense pressure churning in your balls. You gripped her hips, your fingers digging into the soft flesh, and drove up into her one last, final time, burying yourself as deeply as possible.

"R-remember! Don't pull out! Cum inside! Fill me! Heal me!"

"Right! I'm cumming inside!"

The world dissolved into white-hot sensation as you came. It was a torrent, a flood of raw mana and pleasure that seemed to have no end. Rider’s reaction was apocalyptic. Her eyes rolled back into her head, her mouth falling open as her tongue lolled out. A silent, breathless scream was etched on her beautiful face as her own climax was triggered by your eruption.

Rider seemed to pull every last drop from you.

A moment later, with a strangled groan, Shirou found his own finish inside Rin. He gave it everything he had but like last time, it wasn't a particularly long or dramatic series of cumshots. He filled his girlfriend up, tensing and grunting before collapsing against her.

"Mmm." Rin held him close, patting his back gently as she caught her breath. "It’s okay, Shirou. You did well. We did it." Her hug was tender, loving, but her eyes were open, staring over to her left at the scene of your brutal, satisfying union. You and Rider, you weren't lovers, only Master and Servant. It couldn't just be that, right? Or maybe it was? There was a strong, spiritual connection between Master and Servant...

"But that cock..."

"What, haah, was that, Rin?" Shirou choked out, breathless and exhausted.

"N-nothing!"

A complex, unreadable emotion swirling in their eyes.

Rider slowly, shakily, lowered herself onto your chest, your cock still nestled deep inside her, both of you slick with sweat and spent. Your hands rested on her ass cheeks, slowly groping and massaging them. Her face was directly near yours, nearly about to kiss. She only smiled though. Her voice was a shattered, blissful whisper. "Thank you...."

You smiled and gave her ass a nice, polite smack. "You're welcome."