The huge teen slumped onto his bed, spent from the most powerful orgasm he'd ever had. The memories were still etching their way into his mind. He could still remember that at one time he was a skinny 16 year old sophomore, and not the young Adonis that he was now. But those were fading as his new family life began to come to the fore. Jeff grinned as he played with his softening meat through his strained jock, the straps just one good cock-flex away from snapping off his 14" babymaker. His revelry was cut short however as there was a knock at the door.
"Jeffery?" a deep grunt comes from the other side and the door opens. His former-brother-now-giant-father, Derek, peers in, his heavily bearded, ruggedly handsome face scrunching into a scowl as he looks at his son's lewd display. The huge heavyweight of a bodybuilder sighs, groaning as he pinches the bridge of his strong, pronounced nose. "I was going to say that your mother and sister are leaving, but seeing you like this, I think it's better if I send them off without them seeing you."
"Sorry, Dad," Jeff groans, lying flat on his bed, his cock pulsing in his jock. The huge father snorts and turns around, slowly adjusting his own giant tool through his pants. As Derek leaves, Jeff chuckles to himself, realizing this was far from the first time his dads have walked in on him doing this. Even though he was just spent, Jeff felt like with his new genes, he could probably go at it again. Talk about an Italian stallion!
And so Jeff did just that. He leaned back into his sheets and cooed as he felt the cool sheets brush up against his wing-like lats. He marveled at his chest as he pumped his gargantuan, oversized shaft, reveling in how oversexed he was, delighting in how he was the size of champion bodybuilder at the ripe age of 16, bigger and stronger than his fitness model sized dad, Elias.
Speaking of which, he could hear his two fathers send off the woman he once called Mom, and the girl that he once considered his close little sister. Seconds after the door closed, a low slam resonated throughout the house.
"Oof, someone's eager," Elias cooed. "Let me guess..."
"He was at it. Again," Derek replied gruffly, the sound of fabric ripping ringing through the still air.
"Quiet, he'll hear," the smaller man mewled.
"He's probably busy jerking off again," the bigger one snarled lowly.
"He gets it from you, babe," Elias said sweetly, his words interspersed with kisses.
Jeff slowed in beating his own meat, listening in with bated breath as he dads began to go at it loudly downstairs in the living room. Low, animal grunts boom from Derek, the huge bodybuilder the obvious top. The muscular fitness model that was Elias let out heated pants and moans as he was claimed, taken by his beast of a husband.
"Shit, slower, Dare-bear, I can't... take all 16" of you that fast," Elias whined. Jeff's eyes went wide and his hands became a blur on his own giant 14" tool as his smaller father implanted the image of a cock even bigger than his own growing from his giant dad's crotch. His dads slowed their pace, their lovemaking a game of push and pull, meanwhile Jeff beat off with vigor. The young stud nutted inside his jock again, the cup yellowing with load after load of his cum.
After coming down from his second orgasm in this form, Jeff sighed and was ready to hit the hay, when he picked up the pained, desperate moans coming from Elias. Derek was apologizing to his small hubby. It broke Jeff's heart to hear that even though he had great 'improved' his dads, they couldn't get it on like they wanted because they were just too big. That was something Jeff had never anticipated.
Jeff took one final look at himself. He was a huge, musclebound freak as it was, bigger than most men could ever dream of. But he looked at the Chronivac's program with trepidation, knowing that the changes he had planned could potential send him over the top... He hesitated, but the yowl that came from Elias' lips was what got him to commit, no father of his would be left sexually unsatisfied in his marriage!
The Chronivac began to whir as the changes Jeff put in began to take place. Elias' lineage was changed, Jeff inserting more powerful men into his ancestry -- some more beasts from the Mediterranean, the progeny of a viking, a man that could wrestle a bear barehanded from Eastern Europe -- Elias was going to be a monster bottom for his bodybuilding dad, Derek!
Jeff fell back onto his bed as he watched the Chronivac go to work, his eyes getting heavy as the machine's fans lulled him to sleep. He could hear his dads downstairs still going at it. The thrusts began to become harder. An almost inhumanly deep voice roars, "MORE. HARDER, DARE! FUCK THIS BULL GOOD!" Jeff's arousal returned, now with a vengeance. The Chronivac began to alter him as well, the last in line of the transformation.
Jeff groaned as his hands returned to his cock, feeling the appendage growing in his grasp. His pecs pushed his head upwards, his arms were forced further from his torso. His giant balls pinched painfully between his legs and the growing boy widened his legs, his feet hanging off the edge of the bed. With a titan's roar, Jeff came at the same time as his dads, the deep voices shaking the whole house. The force of his orgasm knocked the teen out.
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Jeff groggily got up the next morning, moaning as he felt something in between his pecs. His eyes fluttered opened and his gaze was met with two mountains that jut out of his chest and a ridiculously thick one-eyed snake peeked his head just over the crest.
"Oh God!" Jeff moaned, his hands wrapping around his shaft, his arms heavy and bloated with muscle.
"What have I done?" the teen wondered as he began to pleasure his morning wood.