You sit there, naked and shivering as the woman struts around the room, looking over and feeling her enormous butt. She is distracted by a sharp cry from you as you feel the first changes.
In your sitting position, you spread your legs and look at your genitalia. Your entire package seems to be shifting, pulling closer to your body. Your testicles quickly begin to tingle, causing you to gasp. Your cold body shivers but you barely notice the cold next to the overwhelming sensation in your balls. Your penis is also changing, and in the dim light it is hard to see what is happening, but the sensation is intense, as if it were shrinking and expanding at the same time.
"Ah," says the woman, peering at your genitals in their morphing state. "Being born a human gives you a 50/50 chance of being a male. Other animals, however, have a different ratio. It's much more rare to be male as another animal, which you must become after losing your human aura. It looks like you didn't luck out this time."
Your worst fears confirmed, you watch as your male parts shift and change into female parts. Your heart lurches with the same force it had when you first touched the woman's butt, but this time combined with terrible dread. This can't be happening! You look between your crotch and the woman's face and see that hint of cruelty seems to be growing steadily as you change. She enjoys this, you realize in horror. She enjoys watching men lose their humanity.