Frustrated by his lack of progress with the massive doctor, Diego rushed home to change, struggling in the oversized pants the doctor had given him. He despaired as cum began to drip out through the bottom of one pant leg, bending over to scoop it up and devour it. That was his virus-cum! He had to do whatever he could to reinforce his infection!
Once home, Diego whipped off the gifted pants and slurped noisily, drinking up his bitter seed. He sucked every last bit he could out of the fabric, then scraped what he could off of his huge leg and consumed that as well. "Gotta get bigger," he muttered to himself. It had become a mantra. He would be late for school, but he still showered and changed, freshening up for the day. It was Friday and he felt like ditching, but then he thought of how that would mean missing out on a load of Mr. Dearborn's potent seed.
Diego drove his old car in and, as expected, was fifteen minutes late. He headed for the office, checked in, wrote his own excuse--a perk of being 18--flexed for a couple admiring secretaries, and then headed off to his first class. The day passed slowly--slower than usual, it seemed--each minute ‘til Biology class seemed to stretch into an eternity. But finally that glorious hour arrived, and he sauntered into class, giving Mr. Dearborn a saucy smirk before settling into his seat.
As Diego sat, he did a double take. Mr. Dearborn's shirt was unbuttoned down to his abs, showing off some definite cleavage between a set of very well-defined pecs. Diego drank the sight of the man in, noting the way the instructor's body was hugged by his clothing. Mr. Dearborn definitely looked bigger. Hell, Diego didn't think the man could have buttoned his shirt over his pecs if he'd wanted to!
After class, Mr. Dearborn stood up by the board, staring at Diego as the other students filed out. His eyes were like laser beams, boring holes in Diego's powerful body. Ryan walked by Diego and started to say something, then stopped; he could tell there was something intense going on with his friend and their Biology teacher. He quickly left the room, closing the door behind him.
Mr. Dearborn slowly unbuttoned his shirt the rest of the way, revealing his incredible eight-pack abs. His shirt hugged his powerful shoulders and arms, and stretched across his back, but hung loosely over his chest. "Get over here," the man growled.
Diego stood immediately and hurried to the front of the room. He fell to his knees to unbuckle, unbutton, and finally unzip Mr. Dearborn's pants. Nine and a half inches of veiny meat sprang free once their confinement had been dealt with, jutting out lewdly from the instructor's crotch. Diego opened wide and eagerly swallowed the whole thing, his thick neck bulging as Mr. Dearborn's big dick went down it. The older man let Diego work him over for several minutes, then pushed the younger man's head back until his dick came out with a pop.
Diego looked up at Mr. Dearborn, confused.
"Pants down. On my desk, boy," the older man growled. He reached down and helped Diego stand, then guided him toward the desk and bent him over it. "Been looking at that ass for a while, boy," he chuckled, helping Diego tug down his pants. As the student's big, beefy glutes were finally exposed, Mr. Dearborn gave a low whistle of appreciation. He reached in and began to squeeze and massage Diego's powerful rump muscles, his fingers digging into the firm flesh.
"Um, Mr. Dearborn?" Diego asked, as he felt the older man work his ass over. "Sir?" he added a moment later, after receiving no reply.
"You want my dick, don't you, boy?" the muscular teacher growled, leaning forward, sliding his tool between Diego's cheeks. "I'm gonna fuck you with it," he added, purring in Diego's ear.
Diego had never been fucked before. But he couldn't deny that Mr. Dearborn was turning him on; his own huge dick was throbbing eagerly, audibly banging against the metal desk with a series of hearty thumps. "O- okay," Diego said at last. He gasped as he felt something big and hard enter him. He clenched his glutes reflexively, gripping Mr. Dearborn's shaft, stopping its forward progress.
"Relax," the older man purred, "it'll feel good in a minute." He ran his hands over Diego's mighty shoulders, kissing the younger man's thick neck, nibbling at his ear. Gradually, Diego relaxed. Mr. Dearborn took his time, keeping his big rod in place until Diego's ass had loosened enough to easily push forward. Diego gasped as his instructor began to go deeper, rocking his strong hips back and forth as he pumped his dick into Diego's muscular ass. The hulking student let out a low, shuddering groan of pleasure as sensations like nothing he'd ever experienced before raced through him. He pushed his ass back, eager for more, producing an amused chuckle from the teacher who nonetheless redoubled his efforts, slamming his dick home hard and fast. His brain buzzing from sensory overload, Diego came, his own huge cock spraying all over the side of the desk and into a bowl that had been placed on the floor. His powerful body tensed up, every muscle seeming to flex at the same time. It was enough to drive Mr. Dearborn over the edge as well, and he rammed his dick as far into Diego as he could, shooting his load deep, panting for breath.
---
Diego's ass ached pleasantly. His tight hole and powerful glutes kept Mr. Dearborn's seed bottled up inside him, but he was distracted for the rest of the day, thinking back to his first time being fucked. He halfheartedly sucked Ryan off after school, made his apologies, and went home.
That weekend's workouts were incredible, though. He pushed screaming muscles past their limits and found they overcame what he threw at them. He jerked off constantly, thinking back to being bent over Mr. Dearborn's desk and being taken. By Monday he'd put on five pounds of muscle, bringing him to 315. He was ecstatic! His clothes were tighter than ever and he hurried to get to school, arriving nearly an hour early. He went straight to Mr. Dearborn's classroom, and was pleasantly surprised to find that the door was open. He went inside, and saw the teacher sitting at his desk, wearing baggy clothing and looking over papers. The man looked up. "Lock the door," he rumbled in a deeper-than-usual voice.
Diego complied. When he turned back, Mr. Dearborn was standing up. He looked bigger. Much bigger. "Get over here now, boy," the man commanded. As Diego walked toward him, the older male pulled off his baggy sweatshirt. Diego stopped in his tracks, staring. Mr. Dearborn had passed "fitness model" and looked like a proper bodybuilder. While he didn't have Diego's thickness or the doctor's sheer mass, his muscles bulged with power. "Don't make me repeat myself, boy," he growled. Diego rushed forward, skidding on his knees in front of the big man.
Mr. Dearborn chuckled. "That's better. As you can see, I've been working out. All weekend long. When I wasn’t jerking off, that is…" He bounced his pecs for emphasis. "This morning, I was up to 260 pounds."
Diego's eyes went so wide he felt like they might pop out of his head. On Friday he was sure Mr. Dearborn couldn't have been an ounce over 230, and that was being generous. "That's... that's..."
"Impossible? Amazing? Fucking fantastic?" the Biology teacher teased. "It's all of those things. But that's what the virus does, isn't it? Impossible, amazing, fantastic things? To our bodies?" He slowly pulled down his pants, revealing his muscular legs, one inch at a time. "I had a theory, and Dr. Andrews confirmed it when I went to go see him on Thursday," Mr. Dearborn explained, kicking his pants aside. His underwear followed, his big dick already beginning to chub up. "And so I collected samples. One from him, one from you. And you can see the results!" The teacher raised his arms and flexed them hard, his biceps rising up, beautiful mounds of solid brawn. His posing wasn't polished like a professional's, but it showed off the power in his arms just fine.
Diego's mind was whirling. Someone else had figured it out? Then something else hit him. "He gave you a sample?" he asked in a quiet voice.
"I was very persuasive," Mr. Dearborn chuckled. "Now get on the desk, boy," he added, his voice losing its humor, becoming hard and commanding. His dick was rising swiftly, stretching out to a full ten inches.
Diego half-ran, half-crawled to the desk, pulling down his pants as he went. Mr. Dearborn sauntered after him, picking something up off the desk next to Diego. A moment later he was rolling a rubber up over Diego's big erection. "I don't want to miss any of that, this time," the teacher purred, before slapping Diego's ass admiringly.
The second time, Mr. Dearborn was less patient. He shoved his dick deep into Diego as soon as the younger man’s powerful glutes would permit, grunting with pleasure and exertion as he pounded his student’s muscular ass. Diego could only gasp in shock and lust as he was taken. While Diego was clearly the stronger of the two men--he still outweighed Mr. Dearborn by 55 pounds of pure muscle, after all--he felt helpless to resist the older man’s raging need and increasingly forceful personality.
Again, Diego came first, his huge dick going wild as he filled the rubber that his instructor had carefully wrapped around his dick. Mr. Dearborn came moments later, filling Diego with his virus-laden seed. He pulled the full prophylactic off of Diego’s tool and noisily slurped down the contents. Then he leaned over his student’s fantastically thick and broad back, whispering in his ear. “You’re going to be in my room every morning, before the day starts,” he growled, “And after class, of course. And after school. You’re going to give me your seed, Diego. And I’m going to give you mine. And together, we’re both going to get bigger…”