In Ty's mind, the male part of himself was fighting a fierce battle to control him. He saw it in his mind's eye; a blue penis-shaped form, emanating desires to fill, penetrate, fight.
It had come head to head with a pink form in the shape of two breasts. It was the rapidly emerging female part of himself, rapidly releasing pheromones urging his body to be filled, seek pleasure, seduce.
Both of them clashed at first, seeming even. But then the female form let out a seductive sound of pleasure as it was joined by a pink slit. As he began to massage both parts, the penis and the slit writhed in pleasure, while the female part talked loudly, sexily, in his mind, overriding his male voice. "You like being fucked better than fucking, don't you?" it teased. "You want to play with your breasts and your pussy, and to have your little cock go away."
This made him wish for the new arms to play with his chest, and with that, the female parts in his mind took the male part and began to subsume him into themselves. The male part of his mind writhed in ecstasy as it turned pink and its penis form receded into a clit.
With that, his female mind engulfed Ty's remaining maleness. Her bone and facial structure reformed itself, as did her memories; she rapidly realized she was Tanya, though her powers remained. Finally, her vagina moved up to the front of her crotch, swallowing her penis and testicles into her body, where Ty's male hormones and semen were eradicated.
When Tanya opened her eyes, she was naked, feminine, and overcome with desire.