Your girlfriend turns into a guy.

"I wanna see the other side of the fence I'd love to be a guy."

Without hesitation, she began changing right in front of your eyes. The first wave of changes erasing all her feminine features from her breasts shrinking till they left her flat-chested, her hips narrowing, hardening, and growing muscular to become unmistakably masculine. And as her clitoris relined itself, you could see the outset of her new penis, pushing outwards and paving the way for her testicles to emerge.

"Holy shit!" You exclaimed. "That was amazing…"

"I'm not done yet, hun."

And she was right, as the next wave of changes accelerated her masculinisation. The apparent surge of testosterone triggering the growth of a modest amount of body hair, mostly around her erect member, and armpits with a lesser amount covering her arms and legs. But the changes didn't stop at that, as you could clearly see her jawline gaining definition, and additionally, her hair shortening itself and restyled into a man’s haircut.

Finally, as she moaned in ecstasy, she coursed her hands over her new body, and as she did, her body gained a rather impressive muscle mass spread evenly across her abdomen, biceps, down to her calves.

With her transformation over, she (or more appropriately he) redirected his attention to you. "Well, what do you think?" Asked the blond hunk seductively. His voice oh so deep and seductive.