Himself

Despite wanting to immediately give himself a cock that any porntsar would be be jealous off, Mark knew it would be a good idea to try out some more mundane changes first.

The first change was to his height, firstly Mark moved the slider leftwards until he was about 4'11" and the right until he was over seven feet tall, then he moved the slider to about 5'10", a couple of inches taller than he had been. Mark noted during this test that his clothing was also altered so that it still fit him, which would definitely come in handy at some point.

Next he messed around with his muscle mass, firstly becoming a bodybuilder, then having the musculature of a wimp. Mark eventually settled on a muscular build, hoping he might attract women this way, even though he realised that point was moot thanks to Master PC.

Over the next hour, Mark made all sorts of changes, his hair was green, then purple, then electric blue, his ear was pierced, then un-pierced, then pierced again, his eyes were green, then brown, then orange. He found himself getting lost in the sheer volume of things he could do, and that was only the physical section, and not even all of it. Mark didn't dare touch any of the other sections while testing on himself, lest he make himself into a drooling moron incapable of using a computer.

After he felt content with his tests (so far), he decided now was the time to pump up his cock. Mark moved to the penis length slider and moved it up to twelve inches, and felt the mildly euphoric feeling of his meat growing. Once his dick had gotten to full length, he pulled of his shorts and grabbed it in his right hand, and gave it an experimental stroke. A pleasant feeling rushed up his spine from the sensation.

"I should take this thing for a test drive" thought Mark, as he minimized the Master PC window and moved to his porn folder, putting on his headphones. After about 5 minutes of masturbation, Mark felt himself getting close to cumming, so he grabbed a tissue from the box on his desk and got ready to catch the spunk he was about to unleash. Just as he was about to cum, Mark heard a slightly disgusted tut, and looked back to see his sister near his door. He mustn't have heard her come home because of the headphones

"Close your door next time you decide to jerk off, man" uttered Mark's sister, walking away, and Mark came into the tissue, which he dropped into his wastebasket.