"Surprise!" he said as Jenny looked at him aghast. "I'm gonna turn into a...Dude?" she said as her voice dropped to a lower octave. "Oh shit."
The change was rather rapid as her body began to wiggle and wobble as her chest sucked into itself, the breasts vanishing into a flat male chest. Her hair started to fall out while it turned as blue as the hairs on her toes, leaving her with a large bald spot on the top of her head, with the blue hair forming a ring on the sides. She then gasped as she felt her gender swap physically.
"Woah." HE said. "I'm a guy for real. This is not how I thought tonight would go."
"But it feels good, yes?"
"I guess. What now though?"