Jeff walked in praying Johannes picked something embarrassing, his prayers were answered. Before him, his college senior of a brother was flexing his status at one of the last crazy parties he'd be attending before he needs to be an "adult" after graduation. His costume was that of a penis... not an average penis, a flagrant caricature to represent... Jeff guessed... an alpha male penis?
Rather than being a full body suit which would have limitations based on user's height it was scaled down and had a waist level sack attachment, and a hat that extended off the head as a tip representing a very long, huge balled, hairy, and girthy penis. The unused space around the depictions of a dick weren't unused, it made the pubic area, complete with a jungle of fake 3D hair strands. Wiry strands of hair were sprouting in every direction, mostly off the sack but the shaft had some too. The ball sack was filled with what Jeff could only guess was beachballs and the comical cloth sack they were in ensured they would be kicked with every step.
Jeff immediately burst out laughing and Johannes grabbed and threw a marker at him from his unused white board calendar. The idea of Johannes spending the next year as a walking talking dick was too good! He couldn't have planned it better! If his appearance is functional, going to the bathroom will be a chore and we won't have to worry about him getting anyone pregnant for a year.
Jeff watched in rapt anticipation as Johannes' arms lost mass and the cap melded to his head. The plastic hair's texture changed and the cheap cloth ball sack became fleshy. Johannes moaned in sudden pleasure and Jeff felt a stirring of his own. A few seconds later Johannes was yelling for Jeff to shut the door. Jeff felt it too... it was then that Jeff realized that Johannes isn't wearing an animated penis costume. Just a penis costume, meaning Johannes isn't becoming a walking, talking, sentient, and independent penis, but he is becoming just a penis. For a year...
And as far as Jeff could tell from his boy parts, as the nearest person, if he doesn't do anything, he will be host to his brother over the next year. "Oh fuck that!" Jeff said. Johannes was trying to masturbate but not realizing his whole body needs too be stimulated and that his penis is no longer on his crotch. Jeff turned to go back to his room but every step left a pleasurable yearning that radiated through his body making it hard to continue. He must try to cancel the transformation...
Johannes was now shrinking quickly and realizing something strange was going on. Catching Jeff suddenly bolt, he followed, sure he was up to something. Jeff turned in time to see a dwarf sized penis with legs and weak little arms tackle him. Johannes' face and arms were fading into the penis, so it began to kick and stomp as it continued to shrink. Jeff began to grapple with it and didn't notice as his pants, and then underwear disappeared.
Jeff thought he finally subdued his brother so he quickly stood up, only to realize his lower half is naked and Johannes had attached to his groin taking the place of his normal penis, leaving an oversized behemoth in its place... "Jesus, its so much!" he said in shock at what just happened but not surprised. Just then the attachment finished and and Johannes shrank to proportionate size, much larger than Jeff's average 5.5 erect penis. Jeff was brought to climax as that was how he set to end the transformation of Johannes... He sort of expected his brother on the receiving end of that though...
Jeff cleaned up as his clothing reappeared on him. He entered the bathroom and dropped his pants examining his new equipment. The beach balls had shrunk to clementines, the still erect shaft was surrounded by a dense forest of hair and 11 inches... double his original size. "Johannes, I always thought you were a dick but this is ridiculous!" Jeff said pulling his pants back up..."Let's see if we can fix this."
Jeff entered his room where he was greeted by much newer and more stuff. He was now an only child and his parents had an additional 6 years to stabilize their lives and careers before starting a family. Dad was able to switch career paths at 28 because he could take the risk without a toddler at home. Jeff snickered, "I wasn't the accident, Johannes was."
Sitting at the Chronivac he quickly learned he had to pay attention to his balls while sitting or shifting, crushing them is unpleasant. Jeff quickly looked through the machine finding no option to restore Johannes, he didn't have a profile because he didn't exist as a person here. Jeff tried to rescan Johannes but it kept flooding the screen with his new penis stats and showed no inkling of a sentient being despite "only" being 90% dick for brains. I guess I assumed he'd still have a brain.
Jeff tried, earnestly, to restore Johannes, but it seems like Jeff needs to live with the consequences of his impulsivity.