"...a crossdressing femboy."
"Wait, what?" Your girlfriend paused. However, there was little time left for reflection as your girlfriend's changes had started.
It started as all your girlfriend's clothes suddenly vanished. Next, her body began to change. Her breasts, which were a nice C cup, deflated down to just barely an A cup. Then her hips thinned out, and her butt became rather flat. Her height didn't change much, nor did the length of her hair as she already had shoulder-length hair. However, after she lost an inch, her hair switched from the light blonde it was to black. She then covered her face with her hands as she felt the changes move up there. When it was done, she removed her hands, and she looked just like a cute feminine and girly boy if she had a vagina. That last part was fixed quickly as her clit quickly enlarged as her ovaries dropped down into a sac and became testicles. With the completion of the penis, her changes where done, and she was now he.
Your girlfriend stood there silent for a moment but then moved to a mirror to see her changes. After a few minutes, she turned to you with a stern look on "his" face and said,"Okay, you better explain why you chose this. I thought you said you weren't going to waste your chance? Or is this not a waste? And why do I still have breast?"
"Alright, alright..." You start,"I'll explain why. First thing you should know, for about the past two or three years I have become a little bi-curious. Now, being with you, I never tried anything with anyone cause I just could never cheat on you. So now that we have this room, I figured I could try a little experiment with you as the guy. That way, I am not cheating. Second, I chose some random girly femboy because I wanna try something kinky. To be honest, I think you're very cute when a girly boy cross-dresses into a great looking girl. I figured that since I made you a good-looking femboy, it would be easier for us to go out and eat in public. Heck, imagine if you would go out all the time dressed as a girl, I bet you could fool everybody around you. Besides, I don't think I could do anything sexual with a masculine guy anyway. As for the breast, well,... I have no idea."
"Well," your girlfriend says, looking a little surprised,"I guess I can see what you're saying, but I still wish you talked to me about this before you changed me. Oh well, what's done is done." She takes one more look in the mirror. "I do see what you're saying, though. The hormones this boy is taking are doing a good job on his body. If things keep going this way, I could be a cute boy who dress like a girl."
She then turns back to you with a smile on "his" face and begins to walk over to you. "Anyways, I hope you're ready, cause I ain't going to let you live this one down. You better give me one of the best lays I ever had, or when it comes to my turn, I might not be so nice with your transformation." With that, she plants a long sweet kiss on your lips. You know it's still your girlfriend in there, but right now you just decide to enjoy the moment as things are now. Just you and the very feminine boy.