Ty noticed something as she slowly recovered from her orgasm. Tim seemed weirdly sad. "Are you OK?" she asked.
"Yeah, it's just..." Tim hesitated. "Is it OK if I talk about my kink?"
"Go for it," said Ty sweetly.
"Well... I have a big breeding kink, but now I've gotten to fuck a girl, I feel... empty, I guess," said Tim. "It's like now I've gotten a girl pregnant- you don't have to keep it, obviously!" he clarified. "But now I've gotten to do it, I guess I feel like I don't wanna keep existing. My body's kinda served its purpose."
That pricked up Ty's eyebrows. "So what do you wanna do about it?"
"I guess... it sounds silly... I wish I could get pregnant myself," Tim blushed.
Ty smiled. "What would you think if I told you I could turn you into a girl?"
"Well, I'd love that, but it's totally impossible," Tim laughed.
"That's what you think," Ty replied. With that, he wished for the idea: turn Tim into a girl.
An intense shiver ran through Tim's body, and he looked at Ty in surprise. "What was that?" he asked.
"Just relax," Ty assured him, making him lie flat on his back and getting atop him. "Don't worry, this doesn't hurt. In fact, it feels really, really good."
They both watched in amazement as Tim's body transformed. His skin turned softer and almost hairless, his arms and legs turned smaller and more petite, his figure rearranged itself as his shoulders slunk inwards and his hips expanded outwards, his butt enlarging in kind. Ty stroked Tim's hair as it grew longer and she kissed him, feeling his cheeks and lips soften up under her touch and pulling back to see a feminine face where just before there had been a masculine one.
Tim gasped, his voice sounding girlish where for years it had sounded boyish, as he felt the transforming move to his reproductive system. "We're getting to the best part," Ty smiled. "Are you ready to be a girl, Tim?"
Tim felt unsure he was for a moment- and then he felt his nipples swell up and turn erect as the development they had been denied in the womb finally took place. "Y-yeah!" he moaned as he rubbed them, feeling the flesh around them swell up and grow sensitive. He had breasts, and he loved how they looked.
More familiar sensations ran through him as he felt Ty's hand rubbing his penis. She looked up at him and purred, "Cum one last time with your cock."
"Ohhhh!~" Tim did as she asked, and a fairly large load of seed shot over his stomach. The orgasm felt more intense than any he'd ever felt.
"Good girl," Ty smiled, and her hand continued to rub at Tim's crotch as it transformed from male to female. His drained shaft readily shrank away into a clitoris, his testicles moved up inside her to form her ovaries, and his scrotum split to form her vagina.
As the changes finished, Tammy felt a newfound sense of clarity about her sex. She was a girl now, and it felt good to be a girl instead of a boy.
"Hey, Tammy?" Ty offered. "Do you mind if I do one more thing?"
"What's that?" Tammy asked.
"There's all this semen on your stomach, and I know a much better place for it," Ty giggled. She accumulated a bunch of it on her fingers, and then eased her fingers inside Tammy's newformed slit.
The seed inside the juices that she had put inside Tammy still had an instinctual desire to find and fertilize eggs, and so they raced through her pussy to find an egg which her body had produced while it changed. Once they reached it, her body did not care that the sperm trying to fertilize it had come from his body- the egg accepted the sperm readily, and soon Tammy's womb allowed the xyogte they formed to nest inside her and impregnate her.