Ty knew what he'd like to try first. He'd like to be reborn as an animal. The idea of letting his humanity go for a while and experiencing life in the wild was really enticing to him, and always had been. He eagerly wished for this, and felt everything seem to shift.
His ovum form changed its shape subtly, and while Ty couldn't tell what his new form was, he didn't feel the need to know just yet. If anything, the mystery made it more arousing- he had wished his body away and now had wished his humanity away, ready to be reshaped according to the will of the genetics of whatever creatures would bear him as their young.
And speaking of those creatures, he felt the sex that would lead to his animal form's conception as it occurred. He still had no idea of the species of those animals- only that one was a virile male with a penis, the other was a nubile female with a vagina. They fucked each other instinctively, eager to satisfy their bodies' basest urges to fertilize with his seed and to take his seed inside her, and their arousal leaked through to Ty, who shared in their pleasure as their mating edged his new form closer to its conception.
Eventually they climaxed against each other, and Ty soon started to feel energetic seed surround his ovum form and try to pass inside. At last one did, and a shiver shot through Ty as it directed him down into the female's womb, lodging into place and impregnating her.
Ty now chose to allow himself to know his new species and sex... (A/N: feel free to add your own of course!)