With each thrust, Gwen's body meets yours in perfect synchronization, her moans mingling with the slapping sounds of your hips against hers. She can feel you growing inside of her, filling her up with your alien seed. You promised not to cum for a while yet, but it's becoming increasingly difficult as she tightens around you, milking your cock with every movement.

"One..." she gasps out between thrusts. "Two..." Her words are breathless and full of desire. "Three!"

Gwen's cry echoes through the rooftop as your hot load floods her insides. Wave after wave of thick, potent semen pumps into her, coating her walls and spreading deep within her core. She clenches and unclenches around you, reveling in the sensation of being filled by you.

As you finally finish, Gwen collapses onto the rooftop surface, panting heavily. She rolls onto her back and spreads her legs wide, showing off the evidence of your climax leaking out of her. "Mmm... damn, that felt amazing," she sighs contentedly. "