Ty and Louie slept soundly that night, experiencing one erotic dream after the other. Their dreams were quite similar: Louie getting bigger and sexier, and Ty enjoying Louie's large body.
When he awoke in the morning, Louie had a raging erection, his sizeable cock leaking pre. His sheets were wet with it and with his sweat. The muscled biker reached down, groping the thick shaft, and started to stroke. But as he worked his tool over, he thought back to the night before, the sexy invisible mouth that blew him, and the hot fuck that followed. Reluctantly, he took his hand away from his cock, not wanting to cum just yet, hoping for another visit from the magic mouth.
Trying to distract himself, Louie got out of bed, strutting over to his bathroom. He flexed in the mirror for several minutes, admiring his big new muscles. He pulled out his scale and stood on it: 275 pounds. It looked good on his 6'1" frame. Again, he felt the urge to pleasure himself, but he resisted it. Instead, he headed down to the kitchen and grabbed the container of preworkout shake mix. He poured himself a generous helping and mixed the stuff up. Louie wasn't a gym rat, but he worked out semi-regularly, usually with some old weights in the garage. Today, he planned to hit the gym, instead.
---
Ty awoke to his own case of morning wood. Unlike Louie, the younger man had no hesitation about masturbating. He stroked his dick slowly, imagining Louie's big body. As he worked his tool over, he wondered what the big man was up to. The vision came to him: Louie parking his motorcycle outside a large local gym, slinging a bag over his shoulder, then heading inside. Ty watched as Louie hit the locker room, reluctantly taking off his leathers, changing into black gym shorts and a black tank top. Louie's new musculature was nicely-displayed by his workout gear; the once-loose garments now hugged his larger body.
As Louie strutted out to the weight pit, Ty decided that for every rep in the gym, Louie would gain an ounce of muscle.
---
Louie had a blast at the gym. He had been a reasonably strong guy before Ty's changes, despite his thin frame. But now he was a beast. With every exercise, he was able to lift significantly more weight--almost double, it seemed. He watched his body at work, admiring his muscles as they bulged with effort, tensing as they moved the heavy weights. He watched in the mirror as well, gratified by the stares he was getting. Somehow, he had a feeling that his invisible friend was watching too. That encouraged him, making him lift more, lift harder, pumping out rep after rep, putting his new muscles through their paces. The more he lifted, the more it seemed he could do. His muscles were becoming insanely pumped, bigger than ever, and his clothes were getting tight. It was the most insane workout he had ever had. His dick was rock hard in his shorts and he didn't care; he had nothing to be ashamed of.
Finishing his last exercise, Louie walked up to the mirror. He loved how huge he looked, how utterly massive. He was bigger than before, he was sure of it--no way that was just a pump! He brought his arms up and flexed hard, watching the biceps rise up freakily, his whole body a sweaty, pumped vision of muscular glory.
---
Ty's cock went nuts and he shot a big load all over himself as he watched Louie flex. Ty's hands finally dropped away from his cock as he watched the big biker strut away toward the locker room. Although he had made many changes to people recently, Louie was turning into one of Ty's favorites. Ty was still horny, even after just blowing a load, and was still entranced by the big man. He had to get a closer look.
---
Louie strutted through the locker room like a king, his big muscles straining his sweat-soaked clothing, the wet fabric thin from being stretched over such impressive bulges. The big man grinned at his reflection, loving the way the harsh overhead lighting reflected off of his damp muscles, highlighting them. "Fuck yeah..." he grunted under his breath, bouncing his pecs a few times in the mirror. Again, he was certain that he was bigger than when he walked in--the beast that grinned back at him in the mirror couldn't just be his morning body with a pump!
Louie saw a medical-type scale off to the side of the locker room, and headed for it. He stepped on, and slid the weights to 275. Much too light. He slid the smaller weight further and further to the right, until it read 299. Still not enough! Louie sucked in his breath in surprise, and moved the large weight to 300. The arm clanged, and Louie chuckled as he moved the small weight down, until finally the scale read 310. Louie stared at the number for a moment. Had he really added 35 pounds while in the gym?
"You look great," came a familiar voice. Louie smiled as invisible hands reached around him, caressing his huge arms, his bloated pecs.
"Thanks," the big man replied, "Although I think you probably get some of the credit too..."
Had Ty been visible, he would have blushed. Instead, he stood up on his toes and kissed Louie's hulking traps. "You need a shower, stud," Ty whispered.
Louie grinned and stepped off the scale. He walked casually toward the shower room, pulling off his clothes on the way, unveiling more and more raw, pumped muscle for Ty to admire. Dumping his clothes in a pile outside the shower, the big man walked inside and turned on one of the shower heads. Moments later unseen hands ran across his body, rubbing soap on him, massaging his pumped muscles. Louie was rock hard--both his muscles and his cock--and Ty loved every inch of the big lug.
Ty slowly began to tease Louie's dick, massaging it gently, squeezing it here and there. The big man let out a low groan of appreciation, his muscles occasionally tensing as waves of pleasure ran through him. Ty loved the sight of it, and loved the heft of the big piece of meat in his hands. "I want you to fuck me," Ty said softly.
Louie didn't have to be told twice. Even though he couldn't see Ty, he could still feel him. He grabbed Ty's body and lifted him up into the air, having always wanted to fuck a man while holding him up like that. "Hope you're ready for this," Louie growled under his breath, his dick big and hard and throbbing madly, "because I've been waiting for you since I woke up!" The biker brought the smaller man down, pushing Ty onto his huge tool, which slowly entered Ty's ass, making him gasp in shock at the size of the insertion. But the pain didn't last long, and in moments Ty was trying to take more and more of Louie's glorious dick. The muscled biker was happy to oblige, thrusting deeper and deeper into his invisible partner until finally he slammed it in as far as it would go, making both men moan in unison. For the next ten minutes he used Ty's hole, fucking the younger man ruthlessly, his big muscles driving his dick home with considerable force, while Ty held on for dear life, his hands clutching the big brute's shoulders and traps for support. As Louie fucked Ty his muscles started to grow again, each thrust counting as a rep in the gym. "Oh yeahhh!" he roared, once he realized what was happening. Ty, for his part, was delirious with pleasure, having never imagined the glorious sensations that could come with being fucked by a big, growing muscleman.
Finally, Louie came, his big dick exploding inside Ty an increasingly-intense fuck that ultimately led to the hulking brute jackhammering the smaller man's ass. Louie grunted loudly as orgasm overtook him, his muscles tensing up all over, pumped and flexed to massive size. He held Ty in place, keeping him impaled on his big tool, until every last drop of cum had been expelled. Only then did Louie lift Ty off of him, and slowly set his invisible benefactor on the ground. "Fuck I needed that," the huge biker chuckled. A moment later he mounted the scale once more, eager to see how much he had grown. The number put a huge smile on his face; he was now up to 350 pounds.