Ty quickly noticed a substantial mental change about her- she was far more readily thinking about boys in a sexual way. Imagining big thick cocks, lithe toned flat-chested bodies, firm masculine butts, was exciting her intensely. It made sense, she figured- as a boy he'd mostly been straight, so she was as a girl too. And like all straight girls, her sexual feelings were intrinsically connected with men.
She quickly thought of a wish to satisfy herself, thinking to herself she'd like to create a man she'd find irresistible and would find her irresistible. The air in front of her shimmered, and slowly a naked boy about her age came into existence. He had a handsome, toned body, a cute face with short, soft hair, firm and muscular arms and legs, and between his legs a long thick 7-inch penis and large balls protruded.
Ty felt a shiver of excitement race through her at seeing this gorgeous man, which manifested in a feeling of tension and wetness between her legs. She spread them and grinned at him, and her heart raced as he grinned teasingly back. He climbed atop her, his cock brushing against her stomach and sending a chill through her, and the two kissed passionately and instinctively.
As his firm chest pressed against her boobs, Ty felt a wonderful sense of disconnection from her male self. The desires and instincts guiding her right now were patently female, and she liked them that way. The pleasure she felt as his cock head rubbed along her pussy lips and clit made it even clearer to her that this was the right choice.
He eased his length inside her slit, slowly spreading her open for the first time in her life, and she clung to his firm forearms as he held himself steady, an unfamiliar but intensely pleasant fullness overwhelming her. He leaned into her and kissed her again, and she returned it eagerly, moaning into his mouth as she felt his hips pull back. Her walls that had only just gotten used to how good accommodating him felt tried to cling to him, and she gasped and moaned as he established a pattern of thrusts into her, pushing in deep and slapping her body with his balls before pulling back until only the head remained in her. Just to make it more intense, his hands reached to her chest and played with her soft breasts, his fingers and thumbs sometimes reaching together to pinch her nipples.
Ty felt like she was gonna lose her mind. Masturbating as a boy felt like nothing compared to this, with how warm and firm his cock felt inside her rubbing at her most sensitive points, and how strange and intense having him play with her chest was.
Finally, Ty couldn't hold back any longer, and her pussy walls clung to the boy's cock as she hit her peak, her nipples and clit pulsing with pleasure. Her mind went practically blank, and she suddenly had instinctive clarity about what this boy being so close to cumming in her meant: he would fertilize her. They would fulfill their biological function.
Hearing a hot, low-pitched groan and feeling his cock pulse and shoot his semen into her, Ty's feminized mind basked in that. When she had turned into a girl, his sperm had been converted to an ova, so that instead of filling others with seed, she would be able to take seed inside her and be impregnated. She had embraced the most intrinsic difference between male and female almost unconsciously, and now she recognized it, it felt so good.
Kissing the boy atop her and allowing him to rest on her while his manhood softened, Ty lay there in ecstasy from what her fantasy had allowed. For so long, he had thought of sex as immutable, and her wish had shown her otherwise. From now on, her sex and gender would be whatever she desired, whenever she desired.