One thought in particular really got Ty's creative (and horny) juices flowing. He had a vagina now, so if he wanted, he could get pregnant. To be honest, as a boy who'd had a penis he'd occasionally fantasized about what it'd be like, even though he knew it could never happen to him, but now it could, he really wanted to find out for himself.
Taking a deep breath, he wished to himself, "I wish a boy I find irresistible would come into existence, fuck me and get me pregnant." A moment later, a boy about his age appeared in front of him. His face seemed hazy and undefinable, but his physique was toned and handsome, and seeing the seven inch shaft stood up hard between his legs, Ty felt just as drawn to this guy as he'd imagined.
The boy seemed to smile at Ty, and as he spread his legs the boy slid his penis over Ty's slit and he felt like he could've come right then and there. But then it slid down and between Ty's pussy lips. When Ty felt that, he lost all restraint and moaned intensely, his cock clinging to the boy's cock inside him as he orgasmed around it.
Fortunately for Ty, the boy had enormous restraint, and Ty felt him start thrusting steadily. Ty's heart raced at the odd sensation of the cock head rubbing along the G-spot inside him and the boy's balls slapping against him with every thrust, with Ty soon moving to wrap his legs around the boy and squeeze his amazing firm ass.
Something that threw Ty a curveball was how the boy started playing with his chest. He moved his hands to Ty's nipples and rubbed and pinched them firmly, making Ty groan with pleasure. Part of Ty wondered if he had started to full-on turn into a girl, but he didn't really care that much- all he cared about was just how good this felt.
Pretty soon, the other boy started to lose control, nature taking its course as his cock started to twitch and orgasm approached. The realization of how his role had shifted, and instead of being the one cumming inside, he'd be the one being cum inside, pushed Ty close to his own peak... though the other boy's forceful thrusting in and out of him was certainly doing a lot too.
At last the boy came inside Ty's pussy, both their hips shaking as one filled the other with seed, which raced inside him and would soon impregnate him. Just to make sure he couldn't possibly keep from filling him, Ty's pussy clung to the other boy's cock, not a single drop leaking from him.
And as the boy pulled out, he seemed to vanish from existence, and Ty lay there with his cum settling inside his pussy to impregnate him.