Fill her up

"Do it," you whisper, fingers finding your clit, "breed her."

He notches the fat head of his cock against her entrance—she's already slick, the Frenzy Tab working fast—and pushes in with one long, deliberate stroke that makes Gwen whimper in her sleep, her back arching.

"Fuck, she's tight," he groans, bottoming out, his balls pressed against her ass. "Wet as hell too—the drug's making her soak."

James didn’t give her a moment to adjust. He began to drive into her with a rhythmic, punishing intensity, the sound of skin slapping against skin echoing in the quiet room. Every thrust was deep, burying himself to the hilt in her vagina.

Gwen’s eyes snapped open, her pupils dilated and shimmering under the influence of the drug. She blinked, her gaze darting from the ceiling to the silk scarves binding her wrists, and then down to the massive, pulsing cock disappearing into her body. A sharp gasp escaped her.

"What... what is..." she managed to choke out, her voice thick and hazy.

She tried to jerk her arms free, but the scarves held her firm, leaving her completely exposed. The Frenzy Tab had stripped away her defenses, replacing panic with a primal, chemical craving. She felt her womb pulsing, she began to writhe beneath him, her hips tilting upward to meet his thrusts, her breath coming in short, jagged sobs of pleasure.

James groaned. "You like this, don't you, Gwen?" he rasped, his voice a low growl. "You want this load."

He accelerated, he wasn't just fucking her, he was claiming her. You watched from the pillows, your own hand working furiously between your legs, the sight of your sister’s face twisting in an expression of blissful agony sending your own climax surging toward the surface.

Gwen’s head tossed from side to side, her hair splayed across the pillow like a dark halo. "Wait... stop... no, don't stop!" she cried out, her mind fighting a losing battle against the drug.

She tried to use her voice to command him, to find some shred of control, but the words dissolved into a moan as James hit her cervix with a jarring thud.

"Please... just... fill me... god, please breed me!" she wailed, her back arching off the mattress, her bound wrists straining against the bedposts as she begged for the very thing that would seal her fate.

He let out a guttural roar, as he surged one last time, burying himself as deep as physically possible. You watched, mesmerized, as his body shuddered violently, his cock pulsing inside her as he dumped his entire load, wave after wave of heat flooding into her heightened, fertile womb.

As James finally collapsed atop her, panting heavily, a heavy silence settled over the room, broken only by the sound of their synchronized breathing. He didn't pull out immediately, staying buried within her to ensure every drop reached its destination.

You lay there, your hand finally falling still, staring up at the ceiling. The mission was accomplished; the seed was planted.