You giggled nervously. "So, what did you have in mind?"
"Actually, it's something I've been thinking about for quite some time. There are things I've never told you about myself. The kind of things that might make you question everything you thought you knew about me."
"How bad can they be? We've been together for what, three years? There's nothing you could say that would change how I feel about you."
"Somehow, I doubt that." And with that, she took off her long blond hair. Underneath was a wig cap and a buzz cut.
"So you wear a wig? Is that what you wanted to tell me?"
"No. Feel my chest."
You did, and when you grabbed her boobs, they came right off her chest along with her bra.
"What the hell?"
"They're the latest technology. Just apply makeup and sealing glue, and they feel exactly like the real thing."
"Wait, so if that's not your real hair and these boobs are fake, then what else isn't real?"
"My face is mostly just makeup and a layer of prosthetic. My eyes aren't blue. And-"
She pulled a dick out of her pants.
"How did I not know you had a dick?!"
"You never asked."
Once your girlfriend scraped all the crap off her face, it became clear that she was really a skinny young man with a high-pitched voice. You felt a little disgusted with yourself for not figuring this out sooner.
"It's not your fault, you know. I did everything I could to hide the truth from you. To be honest, I like being a girl. And I always loved being your woman."
"Bullshit. How do I know any of what we had was real?"
And then the boy kissed you. You felt the same warmth and sweetness that you tasted whenever your girlfriend kissed you.
"These lips were never fake. I love you."
"But now what do we do?"
"Well, I do have something I've been having made for myself. It's a woman-suit, or something along those lines. It'll make me a full woman, from head to toe."
"And your dick?"
"Well, I'm not giving that up. You have any idea what it's like to be a woman and be able to pee standing up?"
"No."
"Then stay here."
He left, and when he returned, your girlfriend was standing there, naked and with her dick swinging from where her vagina was supposed to be. You ran up and kissed her again, and then the two of you fucked. And you fucked in every conceivable way. She sucked your dick, then you sucked her dick, you both jerked each other off, then fucked each other in the ass, and by the end the room stank of spilled cum and sweat.
You kissed your girlfriend again, and then both of you got dressed. "You know, neither of us should wear underwear. I want our dicks to be fully accessible for the rest of the night." She kissed you one more time. "From now on, we take care of each other. Understood?"
You smiled and the two of you walked out to enjoy the night.