Parker had been skeptical of aliens until the day he was abducted. When he awoke, it was in a plain, grey room, and he was suspended by his wrists with his ankles pulled apart by chains from the ground. Still able to move his head, he squirmed and looked around, seeing something unusual about his penis. He couldn't quite tell what- perhaps that it looked larger, but he was uncertain from this angle. Between his legs also felt wet.
As he stood, dazed, a screen in front of him showed up as a cameraman appeared though a door in front of him. The camerman was humanoid but alien, with pale skin and large pupils. He was also completely naked with a large penis, and noticing this, the curious earthling Parker began to stir from arousal. Parker then noticed that the video camera was feeding to the flat screen that had at first blended in with the wall in front of him. He could see himself, suspended and naked.
It was then he noticed what was unusual about his penis- the urethral opening was stretched. He gasped and fear shook him, squirming as the well-built camera man zoomed in between his legs. Parker also noticed, now, what was causing the cool wetness between his legs- a vagina. It was dripping a bit, and Parker assumed it was water, having no time to think logically about his recent changes in body.
Another alien entered, now, and the screen showed him.
"Hello, Parker," the new one said kindly. "You're about to become an intergalactic porn-star. How do you feel about that?"
Parker only held still from shock.
"Well, since you are going to be quiet like that, we'll just start. Do you like the new hole, er, holes we set up for you down there?"
"No! This is crazy," Parker finally managed.
"Oh, that's just too bad, because I love them," the alien responded. As he got closer Parker realised he was well-built, his muscles similar to human in anatomy, and toned to shape. "Tell you what- I'll let you know what I'm doing so you can at least figure out what muscles you have to relax when I do it. If you have to scream, use my name, Avo, will you? That really gets me off." He was taller than Parker, only slightly, and definitely wider due to his muscles. His skin was bluish and his penis was smaller than Parker's, around 8". The girth was also smaller- tiny, even, at probably an inch. Avo wrapped his hands around Parker's penis and began pumping him to stiffness, and then started to lube up his own penis.
The cameraman was circling around them, Parker could see from the screen, and was generally going between penis shots, occasionally lingering on Parker's brand new vagina.
"What I'm going to do," Avo started, touching his cock's head to Parker's large penis, "is enter you from here."
"What!?" Parker cried out, shocked and shivering, even though he was restrained.