Ty quickly wished he could use the window to travel to a place, stripped naked and stepped through it so he was right in front of Amanda. The recently-transformed man's eyes widened as he saw Ty and he asked in shock, "Who are you?!"
"I'm the one who just transformed you," Ty replied with an evil grin. "You make a really handsome man, you know."
Amanda was suddenly enraged and practically slammed Ty into the bathroom wall. "TURN ME BACK NOW!" he demanded.
"Or what?" Ty teased. "You'll fuck me in the ass?" Amanda didn't answer, his hard cock twitching against Ty's stomach, and Ty giggled. "I should quickly tell you a couple of things about how I transformed you. I created a virus that would make anyone's sex transform, and once they do their body becomes insatiably horny. You're its patient zero, and it'll spread through you to every human!"
"That's impossible," Amanda protested.
"Says the man who was a woman 5 minutes ago," Ty noted. "Besides, you already just spread it to me. One touch of an infected person is all it takes." Amanda stepped back, horrified and aroused in equal measure, and unable to even look away from Ty thanks to the odd cocktail of pheromones he had started producing.
"Enjoy the show," purred Ty as he felt the virus take root in his body. It rapidly started to slim and soften all over, as his arms and legs and hands and feet and body became more petite and cute and most of their hair receded into the skin. His hips widened and his shoulders narrowed, while his face was resculpted with a softer jawline, no protruding larynx, fuller lips and prettier cheeks. The hair on his head lengthened partway down his back, and he smiled sultrily at Amanda as he developed the sex organs she had had only minutes earlier. Ty's nipples became larger and puffier, and flesh sprouted around them to give him pert C cup breasts. And between his legs, where he had been just like Amanda, he was castrated. His balls moved up inside him, and while his penis sucked back inside him his scrotum receded inwards and split open along its centre to give her a vagina. Once the shrinkage of his phallus completed, it settled atop her new mound as a clitoris.
The intense arousal in the small bathroom was impossible to overstate. Both Amanda and Ty had been subject to the virus's effect, and seeing the sex that had been theirs but now was not left their bodies with an unquenchable desire: they wanted to mate. They HAD to mate.
Amanda pushed Ty against the wall again, but this time instead of screaming at her his lips pressed firmly against hers and he positioned his shaft against the newly formed slit between her legs. He smoothly pushed it inside Ty and they both moaned with pleasure.
Instinctively Amanda's hips started thrusting in and out of Ty, and she clung to his firm body as she was filled by his cock. His large hands soon reached to play with her freshly-formed breasts and Ty panted appreciatively. Each of them was focused on how different their new sexes felt- Amanda couldn't get over how nice his balls pounding Ty as he thrusted felt, and Ty was amazed by how sensitive her G spot was to his cock's rubbing.
Before long their unfamiliar bodies reached their climaxes, and sought the completion of their breeding. Ty's pussy clenched tightly around Amanda's shaft and he came hard and deep inside her, the two of them linked in an upright mating press.
They looked at each other, panting and staring at each other realizing the implications of what they had just done and loving it: Amanda had just fucked a girl raw and impregnated her, and Ty had given up her penis to get made pregnant by a man.