Ty took a deep breath and then said, "...I wanna be your girlfriend."
To his surprise, Emilio found himself kinda intrigued by the idea. He realized the change had made him bisexual, and the idea of fucking a woman as he had fucked men sounded like it'd be an interesting change. "You sure you want to?" he asked.
"I kinda really want to find out what being a girl is like," Ty explained. "Besides, you seemed to like changing sex, so I want to feel that too."
"Fair enough," laughed Emilio. He kissed Ty's head and said softly, "Make yourself my girlfriend, then."
Ty looked down at his body and focused on the wish: make myself into a girl.
He felt an indescribable tingling sensation wash over him as feminine hormones began to accumulate inside his body, and gasped, "Th-this does feel weird... and so n-nice..."
His body was contorting, the unfamiliar hormones guiding it to reshape itself, and he saw his figure slink inwards, turning more shapely as his muscles became more lithe and his hands and feet more petite. He seemed even more small compared to Emilio than he had already, and it surprised him how arousing it felt to realize.
Having shrunken to the size of a young woman, Ty's body set about adopting the features of one. His facial features softened, most noticeably his cheeks and jawline, and his voice's pitch heightened as the bulge of his larynx vanished. His shoulders slunk inwards and his hips expanded outwards while his ass filled out. His skin turned smooth, supple and almost devoid of hair, and when he ran his hands along it it surprised him how it felt nicer and more sensitive.
Ty peered up at Emilio to see the man's eyes were dilated staring at his transforming lover, and that his penis was somehow even larger and harder than it had been. When Ty looked down to see his own erection, a weird realization came over him: I don't need a penis, he realized. He gave himself to his impending castration and emasculation as the sensations washed over his chest and crotch.
His breathing quickened as his nipples swelled, the tips poking out by about a centimeter as the areolae widened, and breast flesh started accumulating around them, soft and sensitive and aching to be touched. Ty propped himself up to see past his newformed C-cup breasts as his cock shrank into his body, the receding shaft getting more and more sensitive. He heard two wet pops as his testicles moved up inside him and reshaped into ovaries, producing ova instead of sperm. His scrotum tucked inwards, and the sac's seal peeled open to form the moist lips of a vagina.
As the changes finalized, the feminine hormones allowed Ty's brain to adapt. He became she, man became woman, male became female. Her sex had been reversed as neatly as taking off a pair of pants and pulling on a dress, and it surprised her how nice it felt. What felt especially nice was how Emilio practically fell onto her, and as she kissed him his body seemed to contrast in exciting ways to her own, even though just minutes ago he'd been a boy.
"My girlfriend's even prettier than I imagined," he breathed into her ear, and she felt her heart racing. He had to make love to her, she couldn't bear for him not to!