Not a full minute before you transformed into Finnick Enders, the door to the bathroom you forgot to lock opened. The real Finn was standing there, a book in hand and a Bluetooth earphone attached to one ear. He looked surprised for a second, then scanned at me from bottom to top and back, and recognized me for who I truly am.
"How'd you recognize me?" I asked, using his voice.
"Psh," He scoffed. "Aside from the shabby clothes that would only belong to you, the way you stand screams like a tired babysitter who works an 8-to-9 job as a delivery guy. And last I check, I have not invented the human cloning machine nor will I likely will. Now, would you follow me to my bedroom so I can assess whatever this is?"
You followed him into his bedroom which looks like your typical teenager's room except for a room extension with full laboratory supplies in it. There are all kinds of junk, from large electrophoresis machines to multitudes of glassware that twists and turns at different angles.
Finn directed you to a seat in the laboratory part of the room where he asked you to undress.
"I'm sorry, what?" you asked.
"Remove your clothes so I can assess our similarities," He said while donning his laboratory gown and stretching rubber gloves on his hands.
To be honest, once you transform into Finn - you don't really have a plan ahead of it. Maybe wank with his lengthy penis and then what? At least Finn is giving you something to do. So, you followed his directives and undressed your clothes. The cold air of the room licks you into a shiver. And the metallic rim of the chair ain't helping.
Finn asked you to stand up closer to him. He crouched down and prodded your balls with a glass stirring rod. The cold stung but you held a calm composure.
"Recording 2520HJ - The Doppelganger. I found the caretaker of my sibling transformed into my appearance. I invited the subject to the home laboratory to assess whether he has completely turned into me or just a close approximation." He poked the rod harder and pushed your balls to the side. "One indicator is the flat mole on the left testicle. The current assessment confirms that the mole is there."
You were about to say something, anything to ask the strange things he's doing, but he took one look at you which made you hush down.
Finn crept closer, and without warning, he gave your flaccid dick a slice of lick, leaving a trail of saliva from your penis to his mouth. "Olfaction and taste of the penis are that of the original. Will test another to diminish the chances of error." He gave another lick, then another, and confirmed it to his record that your dick tastes and smells the same as his. Which makes you wonder how the hell did he know the taste of his penis? How could he recall it to such a clear and memorable degree? You know what? The more you think about it, the more obvious the answer is.
Finn crawled to the other side and spread your butt cheeks open. "I am currently in the possession of a petroleum jelly from experiment H27, and would assess the rectal area of the subject."
With his lubricated index, he inserted it in your asshole which reduced you to a writhing mess. Holy fuck! How sensitive could your body be? You don't think he hasn't touched your prostate yet but that touch alone made you hard as fuck.
"Assessment of the sensitivity of the rectal area is complete. Its sensitivity is akin to the original. Now for the last part of the assessment,"
Finn asked you to lay down on the cold tiled floor. He wanted to do it on the table but it's far too small and his laboratory supplies are in there. You asked him about the bed but he said no. Just, no. Like before, you followed his instructions with no further questions asked.
As you lay horizontally on the floor, your dick is still hard and throbbing from the ass penetration. And it became even harder when Finn resumed sucking on it. He started on the head, giving your uncircumcised head a twirl of his tongue. Sometimes, he would pop his mouth out and suck back in. It gave you a second of relief before the pleasures rushed back in. The foreplay didn't last long because this body surprised you at how fast it can cum. Thick white Semen came out in spurts and filled Finn's delicate mouth.
"Time until ejaculation and the taste of Semen is that of the original. More tests are needed but it seems the subject has already reached his limit, while the original could probably last three or more ejaculations in the following minutes." Finn stood up and sat in a chair. "This concludes the assessment. The original and sample are the same, physically. But the sample has not yet grown accustomed to his new form, as such, he cannot tap the potential of lengthy intercourse. More ejaculation is recommended in the future. End of Session."
Throughout his assessment, you felt like you're just an outsider observer to whatever this is. How could Finn be so pragmatic and uncaring, when he is violating your sexual organs like a typical laboratory on a Saturday night? Nevertheless, the euphoria of the handjob is still fresh in your body and mind. You just laid there on the floor, your chest steadily rising and falling as your heartbeat thumps into a decrescendo. Finn stood above you and tossed you a towel.
"Clean yourself. My parents might probably come home soon, and I still don't have enough data to explain whatever you did." Finn said. "But I expect you to come here soon in my form. We have more assessments to do."