She gets distracted on the way to Michael

Amy barely made it two steps down the hallway when her brother’s half-open door caught her eye. Panting, hips still twitching from the slimy tongue’s aftershocks, she stumbled—then froze.

Andy was sprawled on his bed, sweat glistening on his bare chest, but that wasn’t what made her whimper. His cock—God, his cock—wasn’t human anymore. Thick, veined, and an unnatural shade of glowing green, it pulsed against his stomach, practically dripping with an aura that seemed to mirror the yellow goo dripping from her own tits.

Amy’s breath hitched as she swayed into Andy’s room, her swollen hips brushing the doorframe, leaving streaks of glistening slime behind. The moment her gaze locked onto his throbbing green cock, her pussy clenched around nothing, the alien tongue inside her twitching in hungry recognition.

"Fuck… yours," she slurred, licking her lips as she crawled onto the bed, her leaking tits dragging across his thighs. Andy groaned, his hands fisting the sheets as her trembling fingers wrapped around his shaft—hot, inhumanly smooth, and dripping with an energy that seemed to resonate with the same slick yellow arousal she was drowning in. She seemed completely ignorant of the other, more demonic and disturbing, changes to his cock, only focused on the shaft of Andy's monstrously large cock. It was like there was a voice in her head, whispering, urging her: "Yellow must connect with Green."