This story was written as a commission for JamesFoxes of Fur Affinity. The story is a tour of as many macro themes as could fit into the same story:  growth, muscle-growth, hyper-sex, paws, and even a little inflation and mild vore. The only request was that there be no shrinking. Everything else I could think of with a “macro” angle is present. This is not erotica but—rather—pure porn. Make no mistake: this is fetish material for those who love size. The world-setting (containing Omicron House), and the characters of James White (the human), Taylor Grey (the rabbit), Mack Post (the horse), Tyler Solomon (the fox), Mick Tully (the kangaroo), and Jaydon Golde (the other fox) are owned by myself.

Indelible, part five
©2013 - Sylvan Scott

five
“Mack Post”

“Come in and close the door,” Mack said.
James, having come upstairs to return to his small room with an apple from the kitchen, gulped and hesitated before nodding his assent. He guessed what was coming but part of him wasn’t sure how he felt about it. They’d not hurt him; not really. At most, he’d been teased and toyed with. To some, it would have been overkill, but, for James, it was as if they knew his limits even before he did. Refusing Mack’s request didn’t seem possible. He was far from being the “Alpha Male” of Omicron house. Even “Beta” seemed to be too much.
He stepped into Mack’s room.
The walls were covered in wrestling posters along with a shelf displaying some trophies. His King-sized-and-then-some bed looked like one of those hippy, macrobiotic models with a feather pillow and mattress stuffed with grass. A set of barbells was neatly arrayed in the corner by a press bench. On Mack’s dresser was a personal tattoo kit next to a glass jar of black stuff. The room smelled of sweat and salt but in a strangely comforting way. Mack was dressed in a loose-fitting, voluminous wife-beater T-shirt and hip-hugging shorts.
“Close it,” the black-maned horse said.
“Do I need a safe work?” James quipped, nervousness in his voice.
“Think you need one?” Mack’s expression didn’t change but his voice sent a shiver through James.
The human swallowed and was tempted, not for the first time, to turn and run. He’d seen Mack in the nude, when he’d first arrived. If the equine giant wanted to he could easily rip him wide open.
“Uh, what do ya want?” he asked. He tried not to stare at Mack’s slender, toned muscles or swollen bulge between his legs.
“I heard what you an’ Jayden did yesterday.”
James gulped. “Look, he shouldn’t get in trouble; it was weird but I … I enjoyed it. I got my shape back in no time. You don’t have to call the cops or—”
“Call the cops?” The big man laughed, low, like thunder. “Oh, no-no.” He licked his lips, slowly. “I just want to see just how much of a slut you really are.”
James’ eyes grew wide as Mack smiled and stood.
“Uh, wait; I’m no—”
“Yes you are,” Mack said. “We all are, here. The only difference between us at Omicron House and the rest of the world is that, here, we can explore every last desire we have. And, really, when it comes to being large and in charge, our appetites are pretty damn big. You’ve done well, so far:  you fit in nicely.” He walked over to his weight set and ran a hand over a rack of barbells. “So far.”
“Is … is that what all this is? Some kind of initiation?”
Mack looked over his shoulder and snorted almost like a real horse. “If you wanna look at it like that.” He winked, looking like his tattoo for a second, before turning back to his barbells. “I look at it like you’re a cute, little boy-toy and you got here about a week before everyone else comes back for fall classes. You’re something different in a house of horny, big men interested in different things.”
Mack’s implication about the rest of the guys didn’t go unnoticed.
“Does that mean ....you want me to grow?” he asked, shyly.
“You? Hah! You haven’t earned it, honey. You’re a sweet, little thing with a tight ass, nice package, and decent curves, but you’re still not the equal of even the smallest noob in the house. Granted, none of them are, compared to me,” he said, flexing. He kissed one of his biceps and grinned wider. He did look a bit more buff than James remembered. Had he been working out really heavily over the past few days? He sat down on the workout bench and beckoned James closer. “You keep starin’ at me,” the horse said. “That’s okay:  I get that all the time. You keep lookin’ at my chest, my arms, my groin; you like guys with slender, toned muscle, don’t you?”
James gulped. “I … I don’t know. I’ve never dated any swimmers before.”
“And I don’t look like ‘em, either,” Mack said. “This is a wrestler’s build, human.”
James nodded, agreeing. “You’re like a big...” James trailed off. He had almost described Mack as a big boy-toy. Even though it was true, he didn’t think the equine would appreciate it. “Guy,” he finished lamely.
“Yeah, I’m big. But I’m big all over. Jayden prefers being big in the balls and Mick; well, Mick just loves having fun. And big guys are the most fun, am I right?”
James nodded shyly and walked closer.
“What do you want?”
The horse chuckled. “Nothing difficult. Just help with my work-out,” he said.
James had serious doubts it was really “nothing difficult” but walked up as Mack lay back on the bench and indicated the barbell on the rack. James swallowed, hard, and realized it was set for well over three hundred pounds.
“I, uh, don’t think I can spot you,” he said, honestly. “If it falls...”
“I never drop it,” Mack said. “And you don’t touch my weights, got it? They cost me a fortune.” He beckoned James even closer and lay back on the bench. “Take your clothes off and stand over me.”
James gulped. Here we go, he thought.
Slowly, he pulled his shirt off over his slender torso and, after seeing the huge horse’s appraising gaze, pulled off his shorts. As usual, he was showing his interest already. The horse chuckled, low and deep as James came up to stand right next to the big man’s hips. “Here?” he asked.
“Straddle me,” Mack said.
“Uh...”
“You heard me; and take off those briefs. I want to see what I’m about to enjoy.”
James did as Mack said and, after his briefs had been dropped on the floor, straddled the big man.
“Closer; give me a good look,” the horse said.
James walked closer until he was astride Mack’s muscled chest. His stiff erection bobbed before him and the horse smiled.
“Damn, I was never that small,” he said to James’ chagrin. “But, honestly, you’re a lot bigger than most the guys on campus. Considerably.”
“Thanks.”
Something firm and insistent pressed against James’ rear and he didn’t have to look back to know what it was.
“Bend forward,” the horse said, wrapping his fingers around the three-hundred-pound barbell. “And kiss me.”
This made James stop, cold. He almost never kissed. He once commented to a guy he’d picked up at a campus bar that he didn’t kiss on the first date. While the other fellow understood, having said it out loud had made James realize just how strange it was to be willing to fuck someone but not kiss them. And it wasn’t like kisses were something shameful, either. It wasn’t that he saw them as effeminate. Nor were they particularly special. It was just something … intimate. Kisses were very intimate. He blushed, intensely, as Mack repeated his request.
“C’mon, tiny. Press that muzzle-less face against mine.”
James gulped and, after another long moment, nodded. Every other taboo he’d thought he possessed had been broken since coming here, so why not this one? What was he so afraid of?
Bending forward, he slid his hands over the horse’s expansive chest. Craning his neck, he leaned towards Mack’s chin. Mack smirked and leaned down to press his large, equine muzzle against James’ lips. The aroma of dry, clean straw mingled with jasmine filled James’ nostrils. The soft pressure of lips much bigger than his own, pressed against him. The kiss was moist and surprisingly warm. He closed his eyes and leaned in.
After a long minute, the pressure of Mack’s cock getting more insistent against his rear, James pulled back, heart racing. He was tingling:  nervous with pleasure and sexual warmth.
“Ready for more?”
James didn’t know exactly what Mack had in mind, but he nodded anyway.
“Good,” Mack said. “You’re gonna help me pump some weight.” The big horse reached down to the wall-side floor next to the bench and picked up a bottle. Without looking at the label, James knew what it was. Moments later, the horse’s thick, rough hands were lubing up his ass and coating his monstrous cock. “Now,” he rumbled, “hold steady...”
As Mack placed one hand on the barbell, his other guided his enormous sex to nestle between James’ ass cheeks. It pressed him as far apart as any man ever had; more than that, even. Mack hadn’t even tried to enter him, yet, and already James was feeling the pressure. Still, he stood his ground and pressed his chest against Mack’s.
“Good boy,” the equine rumbled.
He picked up a towel from the floor beside the bench and wiped the excess fluid from his hands. Then, gripping the barbell, he gave a large-toothed smile to James and flexed. He could feel the horse’s pects pulse beneath his bare chest. “Hang on.”
Mack hefted the barbells up and bucked his hips a few inches forward. The welcome fire of sex burned from below as James tried to hold his position. He felt his ass spread and stretch. Stars burst before his vision and, in the haze, he almost thought he saw Mack’s tattoo laughing at him. The shadow of the massive weight passed over him as Mack moved the barbell above both his chest and James’ back. Lying on top of him, James knew that if Mack got distracted, the massive weights would fall. Both of them would be crushed. The danger, he realized, was very real. He got even harder as his heart began to race. His hard cock slid against the short, soft fur on Mack’s stomach. Despite the danger of being snapped in two, he was aroused.
The weights lowered and James felt the cool bar against his sweaty back. Mack grunted and flexed his huge arms on either side and pushed up. At the same time, he slid his hips down for a moment before pushing back and penetrating several more inches. James clenched his jaw as his rear burned with the intrusion. He half-yelled around his grimace. Another rep from the weights resulted in another in-and-out from his rear and he trembled at the sensation. Each time, the giant man stretched him wider and pierced him, deeper. The weight bar rose again. Mack’s muscular body radiated heat through their contact.
This time, the toned horse held the weight at full extension for a long count. His muscles quivered and James felt his huge shaft pulse within him. The delay gave him time to accommodate his partner’s size.
Then, the huge barbell came down and Mack thrust into James, again.
Another three to four inches burned between his cheeks, stretching his flesh and muscle in their wake. Stars blossomed before his eyes again and James bit into the fur on Mack’s chest. He tasted salt and horse.
“Kiss me,” the equine commanded.
James let a whimper escape. He shook his head.
“Please,” Mack repeated, “kiss me.”
James trembled. It wasn’t that he didn’t want to but there was so much happening; so much sensory overload. He looked from the grinning tattoo to Mack’s steely gaze and realized there was a softness in the horse that seemed to need him. There was something longing, despite all the power and mass, that needed a thing so simple as a kiss. Through the haze of something bigger and more insistent than anything he’d ever imagined, he nodded.
James craned his neck again and pressed his lips against Mack’s as the barbell lifted.
Mack pressed his face into the kiss and lifted James up a bit in the process. His body slid back over the horse’s cock even further and he opened his mouth to yell in a mixture of pleasure and pain. Mack thrust his tongue deep into James’ mouth, to the back of his throat. The kiss was rough and passionate. Nothing he’d ever experienced had been a tenth as arousing.
The barbell came down again, pressing James against Mack’s chest. The kiss continued and, with each thrust up and down of the weights, Mack’s cock advanced and retreated.
Deep huffs and pleasure and sweat mingled between the two. But James began to feel the flesh against him grow tighter. Through his half-lidded eyes, he saw what should have been impossible.
As Mack continued, pumping the huge weights up and down over them, his muscles began to expand. The well-toned horse with his wrestler’s build was becoming more buff and more powerful with each thrust. And the growth was only increasing the longer the workout continued.
He thrust his muzzle against James’ lips again and again, the kisses growing even more impassioned. James felt his cock seeping precum over Mack’s swelling abs. His legs began to be forced even further apart as the horse’s hips and legs grew more muscular, too. That cock, so huge and so insistent, buried itself all the way in. James felt himself stretching from the inside like a meat-condom. He could feel the horse’s cock within his torso yet, surprisingly, without injury. Mack, all twenty inches of him, was fully erect and fully embedded.
He pumped his weights more swiftly, now, and the bar no longer felt cool against James’ back.
Mack groaned and thrust, his muscles burning with heat as they grew.
“Look … at … me...” he snarled.
James moaned, his eyes still half-shut.
“Look at me!”
James shuddered and looked deep into Mack’s green eyes. He saw, this close, they were tinged with flecks of deep brown:  almost the color of his fur. But, also, there was something else. There was a power, there. There was a desire. James couldn’t explain how, but he felt it. Not just in the sex but in the energy that Mack was putting into both him and his workout. He felt, for the first time in his life, as if he was truly in the presence of a powerful man.
Fifty reps passed and with a savage snarl, Mack tossed the barbells aside and surged to his feet. The barbells crashed to the floor and cracked the wood. They didn’t fall through. Mack’s mighty hands caught James and held him to his chest while still impaled on his cock. He carried him to the bed.
Mack looked like a giant, despite his height not having changed. His muscles were enormous making his head look small by comparison. James could barely see past his barrel chest. Then, his world turned upside down as Mack tossed him back on the mattress and sheets. The massive, twenty inches slide out of him with an audible sound.
The wind rushed out of him and stars exploded before his eyes, filling him with a light-headed surge. He groaned and felt, for a moment, like he was flying … drifting in a sea of savage sex.
Mack loomed over him. In seconds, the huge shaft was at his rear again. This time, its entry wasn’t slow. Mack pushed with all his augmented strength. Through his haze, James fancied he could hear Mack’s leg muscles actually make his hide creak and strain. The horse pushed in and out of James again and again and again and again. The human spurted cum helplessly, climaxing from the rough treatment. The horse, though, was nowhere near done. He hammered James’ ass repeatedly. His massive, black balls slapped against his ass. Mack’s legs were so thick they looked like tree trunks. His balls couldn’t swing between them. The horse’s arms swelled bigger and thicker, getting as big as trash cans, while his hands stayed firmly locked onto James’ hips.
He fucked James as hard as he could and James felt each thrust.
It felt, each time, like he would be split in two but something kept him whole and able to enjoy the ride.
Soon, Mack’s body was bigger than his mattress, all from sheer muscle-mass. He gritted his teeth and started to shudder. James knew that was the only warning he was going to get. But what could he do? The human prepared himself as best as possible, gripping handfuls of straw and preparing for the coming onslaught. In seconds, he felt a surging blast within. The hot, thick cum flowed into his body as Mack growled and stiffened in pleasure and release. James felt torrents of seed spurt into him:  once, twice, and three times. He didn’t inflate like before—if anything, he felt stretched out and thinner—but as Mack climaxed for nearly a full minute, he knew that the horse had vast reserves. James’ abdomen stretched, but more from Mack’s giant cock than the climactic fluids he was producing. Its heat was warmer than that of his own body and he felt full; he felt incredibly alive! James nearly passed out.
Then, with several mighty shudders, Mack’s body shook. One more spurt, then a second, and soon the giant, muscle-bound horse was finished. He leaned forward, his bed creaking under his weight, and for the first time half-closed his eyes. When he finally re-opened them, those emerald orbs met James with a warm, if tired, smile.
“Ya did well, human,” he rumbled. “Better’n most.”
“Thank...thank you,” James managed, weakly.
Slowly, the huge horse stood and pulled his long, throbbing cock out of James’ rear. A torrent of Mack’s seed came with it. The sheets would have to be cleaned. He didn’t care. He’d just had the ride of his life. Mack ran his finger across James’ chest and lifted some of his spent cum to his lips to taste.
“Not bad,” the hyper-muscular horse said. “Next time, we’ll have to try a longer workout.”
James was surprised, but not overly so, to find himself nodding.
Mack stood and examined his body in the full-length mirror by the closed, bedroom door. “Not bad. Not what I want, long-term, but the workout should last a few hours. Think I’ll go and break a few hearts down at the gym.” He chuckled, reflectively.
“It won’t last?”
Mack looked over his shoulder and shook his head. “A little of it will, but what’s the fun of always having what you want? It’s the getting that’s half the fun.” He winked, mimicking the expression on his tattoo. “And I can always get more.”
James gulped and got dressed. Idly, he wondered if there was such a thing as a “Zeta Male”.

…to be continued…