Back when he was still Arianne, he was able to experience sex as a woman. Orgasm as a woman has always been described as a fuller experience. Arnold was now in an interesting position where he can compare a male and female orgasm with each other. A part of him was deathly curious to compare which one was better while a part of him was disgusted at the thought of touching his penis. This wasn't his penis after all, it was his father's penis that he was about to touch and play with.
Arnold was given a fleshlight by the mad doctor. He could always ignore the fleshlight, but he was feeling a bit horny especially seeing his new body in the mirror. As Arianne, he knew how it felt like to feel horny but this one was different. There was a sense that was he was feeling was something forbidden and unexplored and it makes him feel hornier than ever. His feelings are clearly being reflected physically since his dick was starting to rise from its slumber.
This is the first time that Arnold was able to look at his dick without the doctor's interference. For the first time in over eight months, he was given the privacy to explore his newly formed body. For all intents and purposes, it looked like a regular man's dick. He was amazed that there were no scars visible despite the fact that the penis was transplanted on him. Looking at his cock, a part of him still can't reconcile the fact that this was his father's penis. This was a 45 year old man's penis that was transplanted to a body of a young woman. Looking at it, let alone touching it feels like he's about to do something forbidden.
Another thought then entered Arnold's mind, and that was when the doctor was loudly recording his findings while experimenting on his body. Given that he was heavily sedated while the doctor was messing with his body, the memories that he have might be a bit groggy. And yet he can distinctly remember the doctor mentioning how his father's dick actually grew a few inches months after it was transplanted into his body. Thinking about that gives him a bit of solace since in a fucked up way, he feels like this gives him a bit of ownership with his new cock.
Throwing all caution in the wind, he decided to enter his dick in the fleshlight and started playing with himself. While he was doing this, he was trying to think of images that gets him horny. He initially thought about the guy he was crushing with back in high school. When the image of the guy's face popped up on his head, he felt a sense of disgust. This was weird since he never felt like this before. It's as if his brain has overrode the fact that he was originally an 18 year old girl. This is actually due to the fact that the doctor mentally adjusted Arnold's sexual brain to think of himself as if he's always been a middle age man in his 30s, and thinking about a teenage boy to get horny made him feel a bit disgusted with himself.
His brain then started to form images of busty women. Unknown to Arnold, these were the images that the doctor subliminally imprinted in his mind while he was experimenting on him months prior. The doctor was able to solidify Arnold's sexual preference stimulating his dick to get hard whenever he was shown women with curves and ample breasts. The image of a blonde busty woman that was forming inside Arnold's head caused Arnold's dick to go full mast, finally revealing to the newly formed man the full 8 inches of his transplanted equipment. As if it was second nature to him, Arnold kept on motioning the fleshlight up and down until he grunted and finally cummed inside the fleshlight.
Little did Arnold know that the doctor was watching the entire time. He was very pleased with what he has seen since it confirmed that Arnold's new sexual orientation is that of a straight middle aged man's. Also, the fleshlight that he gave Arnold was actually a semen collector as well. The third phase of the doctor's experiment deals with figuring out the genetic offspring that Arnold will produce. Will the semen contain Ruben's DNA? This makes sense since the transplanted testes were Ruben's to begin with. But considering how well Ruben's sex organs have settled to Arnold's body, the doctor believes that the new genetic material will be solely Arnold's. He needed a semen sample to investigate that hence why he needed the cum sample that the fleshlight has collected for him.
The first two goals of the experiment has been fulfilled. His theory that there will be no rejection when transplanting the genitals of immediate family members from one another has been validated. This goal was actually more of a success than he thought considering how well Ruben's penis has settled in his daughter's body upon transplanting it. Another goal that has been validated was the ability to create sexual byproducts by the transplanted genital. Seeing how Arnold was able to cum just like a regular man, the doctor was pleased to see that he was functionally identical to that of a virile man.
The final goal of the experiment is for Arnold to create an offspring on his own, and observe whose genetic material will be dominant to his eventual offspring. Will it be Ruben's or will it be Arnold's? It could even be both. Only time can tell, but for now, the doctor needs to slowly reintegrate Arnold to society.