A Robot

... a robot." The mad scientist said.
"A robot?"
"Basically, I took the head of a robot and grafted it onto your body. By the way, you've been out for a week. It has gotten used to your body in the meantime."
"What do you mean?"
"Well, it didn't think sexual desire would be something I'd have to factor for, at least initially. Honestly, I was completely wrong about that. Once it could feel, within two days it had masturbated, and it's had sex at least three times since. Once was with the woman whose body you now have, except I transplanted her head onto a male body, and once was with a man who now has a woman's body."
"Don't you find this a bit, well, fucked up?"
"Surprising is more the right word. No one was forced for sex, it was all consensual. To find sexuality is something that can be learned by an AI, that's something that even most science fiction writers would not have guessed at. In fact..."
The doctor turned on a monitor, and wheeled Jon around to show him the screen.
"There's your body now, actually."
Jon watched in shock as his body, with a round, robotic head, was feeling up the breasts of a beautiful woman. Below her neck was perfect tan skin, ample breasts, and killer legs. She looked like she waxed, because there wasn't a hair found on her below the neck. She was wearing nothing but black stockings and knee high black boots with stiletto heels. However, where the shoulders and the neck met, above it was the head and neck of some fifty-something redneck with a gray beard and paler complexion. His eighteen year old body was currently fingering the redneck with one hand while rubbing a breast with the other. The redneck moaned, and used his now-feminine hands to feel up Jon's body's chest and back. The redneck then sat up and started to jerk off John's body, the robot moaning in electronic pleasure. The robot then had him stop, then it started to feel up both breasts, and then, with the help of the redneck whose head was attached to the woman's body, pushed itself into the redneck's new pussy. Both moaned as the robot-Jon and the redneck man-woman felt each other up, the robot now feeling up the man-woman's ass and thighs, rubbing Jon's hands against the nylon of the stockings. Both kept going, kept moaning, until the man-woman started to orgasm, swearing in pleasure. The robot kept going, and then pulled (his?) dick out, letting it cum on the breasts of the man-woman.
Jon didn't know what to say to what he had just witnessed.
"Tell me, this just a fetish, or do you do this for actual science?"
"Honestly, I don't really have sexual desire." The scientist said. "A defect, I guess. Maybe this is why I'm fascinated by this. It's alien to me. Anyway, if you want, I can put you in that room, or we can do something else. Your choice. However, your body is mine for at least one more week, so don't bother asking for it back."