Tag had seen Mark quite a few times in the lab and had already made up his mind that Mark was strictly straight, no doubt about it. He’d even heard him brag about his hot girlfriend on several occasions. Besides, his radar had told him to steer clear of Mark; something about the guy just felt off. Tag wasn’t the type of person to put up with blowhards, except Mark was one of the hottest guys Tag had ever laid eyes on. He’d wondered on several occasions how a guy like him ended up in a lab among the chemistry nerds. Then again, he wasn’t always keen on judging a book by its smoking hot cover.

On that particular day, when Tag discovered, or perhaps uncovered, Mark’s other side, the lab was all but deserted. Two girls were sitting at a workbench opposite Tag, but far enough for him not to hear what they were babbling about. Mark sat at the closest workbench with his back facing Tag. Instead of tending to his boring experiment, Tag was admiring Mark’s broad shoulders and muscular arms tucked beneath his lab coat. He could also make out Mark’s thick haunches pressed against the backless seat under his buttocks.  

When Mark stood up and turned around, Tag noticed that his crush had either unbuttoned his lab coat or that he’d been too lazy to button it in the first place. He tried to avert his eyes in fear of being seen leering. His eyes, however, had already registered the ample bulge between Mark’s thighs. The latter was wearing blue jeans that weren’t that tight. Still, that bulge was as clear as the weird expression drawn on Mark’s face.

Tag blushed and excused himself out of the lab. When he returned, he noticed that the two chattering girls had left. He and Mark were alone. On his way back to his workbench, Tag couldn’t help but throw another look in Mark’s direction. A faint smile had appeared on Mark’s face, and his hand now seemed to be caressing that ever-growing bulge. When he became aware of Tag’s helpless stare, Mark spread his legs as if to make his still concealed, yet clearly visible, erection more accessible.

They heard one of the two doors to the lab open. The girls from earlier had apparently returned to search for something they had left behind. They seemed in a hurry and paid no attention to Tag or Mark.

“How was it possible that that bulge is still growing?” Tag thought to himself.

Meanwhile, Mark, with that curious smile on his face, kept on rubbing his dick, the outline of which had become quite discernible across the right thigh. He turned his head to face Tag, and his smile grew bigger.

Tag drew closer. With his free hand, Mark beckoned him to sit in one of the backless seats next to his. Tag obliged and, once seated, reached out to touch Mark’s crotch and started massaging his hard-on. He felt his own dick starting to swell, but decided to focus on Mark’s dick instead. Tag then proceeded to unbutton Mark’s pants. He reached in with his hand and tugged at the meaty cock until it sprung out of the blue jeans.

“Holy fuck!” whispered a bewildered Tag.

“Put it in your mouth boy,” Mark demanded.

“But… but… what if someone comes in and sees us?” Tag asked timidly.

“No they won’t, you slide yourself down beneath the workbench and do your job, don’t worry about it.”

Tag, once again, did as he was told, no further questions asked. He went down on his knees and positioned himself between Mark’s thighs, his less than average-sized body tucked perfectly underneath the workbench. He was now directly facing a juicy, fat dick of average length but sizeable girth. The head was especially meaty and the slit was already oozing pre-cum. Mark looked down at Tag and, with one facial gesture, ordered him to go at it.

When Tag reached out his hand to stroke the pulsating erection, Mark stopped him. He looked up inquiringly, concerned that he had done something unsatisfactory.

“Tsk-tsk, no hands. Use your pretty mouth, boy,” Mark murmured.

Tag, eager to please, pressed his moist lips against the oozing tip. Mark held Tag’s head basketball style and pulled it closer. He felt his dick touching the back of Tag’s throat. Gagging and taken off guard, Tag tried to pull away, but Mark had already locked his head between two beefy thighs. His dick now buried to the hilt inside Tag’s throat, Mark let out a husky groan and flipped his head in ecstasy. Next, he let go of the poor cocksucker whose face had turned all shades of red.

Tag gasped for breath and rested his head on Mark’s beefy thigh. He looked up at Mark, who nodded at him and said, “Good boy.”

That was enough to re-energize Tag’s insatiable appetite for dick. He kissed Mark’s thighs and sniffed at his crotch, inhaling the manly musk that put him into overdrive. He again swallowed the dripping cock and started sucking on it, his head rhythmically sliding back and forth.

“That’s it, all the way down that tight throat,” Mark said breathlessly.

The door to the lab opened again. Upon hearing that, Mark immediately slid closer to a tall box of lab miscellany in an attempt to hide Tag. He also pushed his own chair forward, further closing the gap underneath the workbench. Meanwhile, Tag kept up the now hypnotic pace, swallowing every inch of Mark’s girthy dick at a perfect tempo.

“Hi. Have you seen Tag?” asked the guy who had just entered.

“Ugh… he… mmm… I don’t know, he left a few minutes… ago,” stuttered Mark. The intense sucking action that was going on behind that cardboard box had left him speechless. He was afraid he was going to explode while talking to whoever that was who stood before him.

“Well, please tell him his boyfriend was here. And tell him I’ll be waiting for him in the cafeteria. I called and texted him, but he must have put his phone on silent.”

“Sure… ugh…”

“Are you okay there?”

“Oh… ugh… yes, just a stupid headache.” Not the most convincing response, Mark thought, but the other guy didn’t seem to care that much.

“Oh, headaches are the worst. Sorry. You take care.” And with that, he left.

Mark pushed back his chair and saw that Tag had turned a burning shade of red. He was still going at the dick like an automatic sex-machine. Drool and sweat covered his swelling lips and red face, and dripped all over his lab coat and pants. The boy seemed totally and utterly hypnotized.

Mark said: “Boyfriend huh? Ugh… the way you’re sucking my meat right now, I’d say your boyfriend’s a lucky dude.”

Tag looked up at him with half-open eyes and a dick deep inside his mouth. He didn’t seem to hear Mark’s remark and instead, kept on sucking, slobbering all over the fat cock which overstimulated his salivary glands.

“Ugh… I want to fuck your pussy, boy,” Mark continued in a hushed whisper, “I hope that boyfriend of yours hasn’t already fucked it beyond repair.”

Tag, still sucking away, moaned like a little whore, signaling his insatiable desire for Mark’s dick to stretch him wide open. His boyfriend might’ve overworked his ass on the daily, but he wasn’t at all worried. Mark’s dick was can-of-coke thick. Even a sloppy hole would feel tight around his girth. If anything, Tag’s boyfriend would notice a difference tonight while fucking him before bed. But Tag wasn’t a bit worried about that either.

“Okay, boy, I’ll lock the lab doors this time. You drop your pants and make sure your pussy’s ready for my dick.” Mark took his cock out of Tag’s mouth, slapped it against his hand, and then hid it inside his pants. Tag still seemed dazed as he eyed the bulge with an open mouth from whose sides overflowed trickles of saliva mixed with Mark’s savory pre-cum.

When Mark came back to the workbench, he found Tag leaning against it, coatless, his pants and briefs around his ankles, his ass lifted up, and his back bent like an upside-down arch.

“Good boy,” he spoke into Tag’s ear, “You really want my fat cock, don’t you?”

Tag tried to moan but Mark, standing behind him, had already placed his hand over his mouth.

“Shh, this is going to hurt, but you’re gonna have to be silent.”

Mark then produced a bottle of some lubricating agent—originally only to be used in experiments—and dipped his finger inside. After that, he pressed his forefinger against Tag’s puckered butthole. It slid inside comfortably.

“Not so tight after all,” Mark breathed heavily against the back of Tag’s neck.

He slid his middle finger next. Then his ring finger. Tag couldn’t but let out a slight moan.

“Tight enough, boy. Your pussy will wrap perfectly around my cock.”

Tag felt Mark’s dick press against his right butt cheek. He could feel the juicy mushroom head dripping pre-cum on his smooth skin. The head then pushed against the lubed hole and, with a small thrust, popped inside.

“Fuck,” whispered Mark, breathing down Tag’s bent-down neck. “That’s some good warm pussy, boy.”

What happened next happened a bit faster than both Mark and Tag would have intended. After burying his dick to the hilt inside Tag’s ass, Mark proceeded to thrust it back and forth, in and out, all the while stifling Tag’s moans and whimpers with one strong hand. The other hand kept slapping Tag’s round and slightly jiggly butt cheeks. At one point, Mark spread the butt cheeks with two hands, slid out his exceedingly engorged dick and announced that he’d opened Tag’s hole so wide, it’d probably need a few stitches.

Ten minutes and a million bumps and bangs later, Mark’s huge balls, which had been smacking relentlessly against Tag’s bum, clenched and throbbed repeatedly. From them, the sweet nectar that is cum, surged to the outside and deep into Tag’s bowels. Mark grunted and heaved like a wild bull, and Tag imbibed the manly sounds in ecstasy.

“Don’t let one drop of my cum get on the floor, boy,” Mark commanded. “Come on, pick up your pants and go see your boyfriend. He might want to have a go at it next, it’s already lubed, locked and loaded.”

He chuckled, put his still hard dick back in his pants, and casually went back to his bench.

Tag, eager to obey orders, quickly slipped his briefs and pants back on. He’d just started for the door when Mark turned around and, with a smug smile, said, “Expect this more often, deal? My girlfriend’s pussy doesn’t come close, I’ll give you that.”

Tag nodded complaisantly and walked out. In the elevator, he felt Mark’s warm cum pouring out of his fucked hole, drenching his briefs. He put on a genuine smile and went to see his boyfriend in the cafeteria.