Pikachu marveled at her new two foot height, looking over herself and then back at Ash, wondering if she could still ride on his shoulder like this. As she gazed at the sleeping trainer, she suddenly felt a strange warmth, different than the one that had caused her to grow. She felt... flustered, like she was blushing... and a strange feeling between her legs. She squeezed her thighs together as strange urges began to fill her mind. Unable to help herself, she crawled towards him, sniffing and smelling something that her body told her she needed. Carefully, she removed Ash's blanket, looking at his legs, specifically at the slight bulge at his crotch.
She licked her lips, the heat within her rising. All sense and reason went out the window; instinct took over, telling her that she absolutely needed this. She carefully crawled on top of him, undoing his pants with her little hands, guiding his cock out into the open. She pressed her nose into it, inhaling and taking in his intoxicating scent, then took a long, slow lick along its length. She smiled as it got hard, then bit her lip as she felt her new pussy demanding to get a taste of it as well. Unable to resist her urges, she moved to try and get the dick inside of her needy snatch, moaning softly as she suddenly felt herself growing again, gaining another foot faster this time. Now over three feet tall, the task of getting his dick inside of her was easier, and she moaned louder as she felt the head pushed into her pussy.
Pikachu began to pump her hips, pushing down onto him more and more with each thrust. Ash moaned in his sleep, seeming unaware of the growing, horny Pokemon riding his dick. And my, was she growing, the stimulation seeming to speed up her growth. Soon enough, she was five feet tall, about his height, bringing her hips down onto him to take his cum as he orgasmed in his sleep. She felt it pump into her with a sense of satisfaction... though she wasn't finished herself. A thought did cross her mind in a moment of clarity: if she kept growing, Ash's dick wouldn't be able to fill her for much longer. Plus, there was a strong chance he would wake up after all that...