Comic by Yetigo
Professor Tok turned to address the class. "Now that we have examined the subject's baseline anatomy and responses, we will begin preparing him for impregnation. The first step is to induce lactation so that the subject can provide nourishment to the offspring once they are born."
The professor picked up a gleaming metal tray laden with an assortment of strange tools and devices. It selected a wicked-looking syringe filled with a glowing green fluid.
"This serum contains a potent cocktail of hormones and growth factors that will stimulate the subject's mammary glands," Professor Tok explained, tapping the side of the syringe with one of his tentacles. "Normally, lactation occurs naturally in females as a result of pregnancy and childbirth. However, with the aid of science, we can trigger milk production in males as well."
Two smaller tentacles snaked out from the professor's body, each one tipped with a gleaming needle. They hovered over Juro's chest, poised above his pale nipples. Juro's eyes went wide with fear and he renewed his struggles, but the energy bonds held him fast.
"P-please, don't," he stammered out, but his plea fell on deaf ears.
The needles sank deep into the tender flesh of Juro's nipples and he screamed as liquid fire seemed to explode through his chest. The plungers depressed, emptying their contents into his body and Juro felt a tingling heat spread outward from the injection sites. His nipples swelled, flushing a deep, dusky pink as they puffed up.
Professor Tok pinched one engorged nub between its suckers, rolling the sensitive peak back and forth.
Juro gasped, shuddering at the unfamiliar sensation. Pleasure-pain rocketed straight to his groin, making his flagging erection surge back to full mast.
"Very good," the professor said approvingly. "The glands are already responding."
The alien reached for another set of devices on the tray - two clear suction cups trailing tubes that led to a quiet humming machine. Professor Tok affixed the cups over Juro's obscenely swollen nipples and they sealed to his skin with a soft hiss, enveloping the entire areola. The machine whirred to life and Juro felt a rhythmic tugging on his chest as the device began to pump.
Professor Tok adjusted the settings on the machine's control panel. "These pumps will provide the necessary stimulation to encourage lactation. The serum will accelerate the process.”
The pumps began to pulse and suckle in a steady rhythm, tugging on his swollen nubs relentlessly. As the pressure increased, Juro gasped, his back arching involuntarily. The sensation was intense, just bordering on painful, as it stimulated nerve endings he never knew existed.
Despite himself, Juro's mind flashed to his farm, to the cows he milked twice a day. He had attached pumps just like these to their swollen udders countless times; the machines pulsing and pulling until the milk flowed freely. Now here he was, splayed out like a prized heifer, his own teats suckled by alien technology for their perverse experiments. The comparison filled him with a confusing mix of revulsion and shameful, reluctant arousal.
Professor Tok monitored the read-outs on the pumping machine with clinical satisfaction. "Very good. The subject's mammary glands are responding well to the treatment. With regular stimulation, he should begin producing colostrum within a few cycles, followed by a steady milk supply." The alien reached out to stroke along Juro's jaw almost tenderly with one tentacle tip. "You will make an excellent mother."
Juro shuddered at the touch, trying to turn his head away. But deep within him, some traitorous part imagined it — his pecs swollen with milk, alien young suckling hungrily at his dripping teats...
There was a clicking sound and Juro’s body rotated in the air, giving the classroom of students a view of his backside.
Something slippery slid between Juro’s ass cheeks and pulled them open.
"Now, we must prepare the subject's birthing cavity,” the alien said. It poked the tip of its tentacle against the rim of Juro's anus. “This will be uncomfortable for the subject, although some male humans do experience pleasure when this rear orifice is stimulated.”
Juro squirmed against his bonds. “H—hey, wait a second now...”
The professor’s slick tentacle probed deeper, pushing insistently against Juro's tight asshole. "Observe how the external anal sphincter reflexively contracts to prevent penetration," the alien remarked. "However, with sufficient lubrication and applied pressure..."
Juro clenched his teeth, muscles straining as he fought to keep the tentacle out of his most intimate place. But the alien was relentless, their slick tentacle probing and circling, coating Juro's crinkled opening with slippery fluids until, with an sickening squelch, the tentacle forced Juro open.
Juro gasped at the burning stretch. His virgin hole spasmed madly around the foreign invader. "Nnngh! Take it out!" His voice sounded more desperate than commanding.
"As you can see, the anus and rectum are highly flexible, able to expand to accommodate a variety of sizes," Professor Tok explained as the tentacle spread Juro open with a slow, relentless push. “This will be the entry point for impregnation.”
Professor Tok's slick tentacle glided back out of Juro's clenching hole with a slurp. The human gasped in relief, though he could still feel the phantom sensation of being penetrated. His reprieve was short-lived.
"Pay attention now, students," the alien said. "I will now demonstrate the elasticity of the rectum."
Without warning, Professor Tok plunged its tentacle back into Juro's ass, burying it deeper than before. Juro's breath hitched as his muscles parted, arching his back as Professor Tok's tentacle forcefully spread his inner walls open again.
Professor Tok pistoned the tentacle in and out, establishing a punishing rhythm. Juro's butt cheeks jerked and jiggled with each thrust. It sounded like someone got their boots stuck in mud and were pulling it out over and over again.
"As you can see," the professor said, "with vigorous stimulation, the internal muscles will tire and allow deeper penetration."
"Nnnngh..." Juro groaned through gritted teeth as a deep thrust brushed against a spot inside him that made sparks shoot up his spine. His softened member gave an interested twitch against his thigh.
"Note the specimen's physiological response," Professor Tok said. "This is due to stimulation of the prostate gland." The tentacle pressed insistently against that spot and began to rub.
"Ahh! Ohhh..." Juro shuddered and squirmed as the alien massaged his pleasure button. His cock rapidly swelled back to full hardness, a pearl of pre-cum beading at the tip.
Professor Tok plundered Juro's anal tract, gliding through the copious slick its tentacles were secreting. Lewd wet sounds filled the room. Juro’s hips thrust back and forth, torn between flinching away from the intensity and rocking back onto the invading appendage.
"P-please..." Juro babbled deliriously, no longer sure if he was begging for it to stop or for release.
But the alien continued its clinical torment, expertly working Juro's body as it lectured. "Prolonged prostate stimulation can lead to a different type of orgasm in human males. One that does not require ejaculation."
Professor Tok withdrew its tentacles from Juro's quivering body, leaving him panting and teetering on the edge. “It appears the rectal passage will need to be stretched to accommodate the girth of both our genitals and of our offspring during delivery.”
Behind Juro, the alien pressed a nozzle against his entrance, still slick with tentacle lubricant.
"To do this, first we will expand the subject’s cavity with liquid, taking measurements of the internal dimensions."
The nozzle slid in easily and Juro felt something warm flow into his body, filling him up from the inside. More and more liquid pumped in, making his belly swell and cramp.
Juro groaned as his belly bulged like a perverse balloon, his abdominal muscles straining against the unnatural pressure. It felt like a lead weight was settling in his gut, bloating him fuller and tighter with each passing second. Cramps seized his overtaxed bowels as they struggled to accommodate the massive volume being forced into them.
Juro sucked air in through his nose, trying desperately not to bear down and expel the invading liquid. He had a sickening feeling that resisting would only make the ruthless professor prolong this torment.
The tentacle twisted, shifting the nozzle inside him. Juro gritted his teeth and bit back a wail, tears leaking from his clenched eyes as the liquid stretched his insides wider than he ever thought possible.
Just when Juro was certain he could take no more, that he would rip apart at the seams, the pumping finally ceased.
"Subject's internal capacity has increased by 50%," Professor Tok noted. "Elasticity of the rectal walls is promising, with no signs of tearing or rupture even at this extreme expansion."
The nozzle pulsed once, then withdrew.
"No, don't!" Juro cried out, but it was too late.
Liquid gushed out, shamelessly spraying onto the floor between his spread legs. Juro sobbed brokenly as his body continued to expel the fluid beyond his control, his asshole winking at the class full of students as it spasmed. Finally, the last of it oozed down his taint and dripped off his balls.
Professor Tok hummed approvingly and picked up a long, gleaming speculum from the instrument tray. Shaped like a tapered cone, its polished surface was etched with markings to note incremental measurements.
Juro could only whimper in dread as the device was positioned at his back entrance. The speculum pushed into him and Juro swallowed a yelp as it glided up his passage with ease thanks to the professor’s ministrations. Once inserted to the hilt, Professor Tok turned a knob on the side, ratcheting the device open.
Juro howled as he was split wide, the speculum pushed his tender walls apart. Cool air touched his insides, exposed and vulnerable to alien eyes. The instrument continued to crank wider, the increments ticking by, stretching Juro to lengths and widths beyond the scope of human anatomy.
Professor Tok peered into Juro's stretched, gaping hole, examining every intimate fold and crevice. "Fascinating," the alien trilled. "Note how the rectal tissues have begun to change color and texture as a result of the hormonal treatments and stimulation. The mucosa is taking on a pinker hue and the rugae are smoothing out, making the passage resemble the human female's vaginal canal."
Two slender tentacles slithered into Juro's splayed hole, probing deeper until they found the firm round bulb of his prostate. Juro yelped as the sensitive gland was stroked and prodded, sending confusing sparks of pleasure shooting up his spine.
"The prostate is an erogenous zone in male humans," Professor Tok explained as it ruthlessly kneaded the swollen node. "Stimulation can produce intense sensations of pleasure, even triggering orgasm."
The alien reached for another syringe on the tray, this one filled with a phosphorescent purple liquid. "To ensure a hospitable environment for our offspring, we must adjust this gland. This serum contains growth factors that will enlarge the prostate and increase its sensitivity, allowing it to take over as the primary pleasure center."
Held open by the speculum, the professor easily reached into Juro’s cavity and pierced the needle into Juro's prostate. The alien depressed the plunger, injecting the contents deep into the defenseless tissues.
Juro wailed, back arching as liquid heat suffused his loins. His muscles clamped down, trying to protect themselves, but the speculum held Juro open and helpless against the violation.
Professor Tok picked up another item from the tray. It looked like a small metal cage. "To ensure the subject’s total devotion to his new role, we must limit his penile orgasms and train him to derive pleasure solely from his birthing passage." The alien stuffed Juro's penis into the device and locked it into place with a definitive click.
Juro’s cock was completely encased, trapped in unyielding metal that pressed in from all sides. No amount of straining or arousal would allow him to gain any friction or relief.
"From now on, the subject's pleasure will come only from internal stimulation of his prostate and rectal sheath," Professor Tok declared. "His penis will no longer play any role in orgasm. He must learn to climax through penetration and pressure on his prostate, stimulation of the nipples, and/or penetration of the throat."
Juro hung limply in his bonds, body quivering with exhaustion and overstimulation. His puffy, swollen nipples throbbed in time with the relentless suction of the milking pumps, the sensitive nubs now a deep, angry red. Thin rivulets of creamy fluid began to dribble from the engorged peaks - the first traces of milk production as his body responded to the aggressive alien treatments.
His heavy balls churned uselessly in their sac, engorged with seed but trapped by the unyielding cage encasing his genitals. The human's hips rutted uselessly into the air, seeking any hint of friction or relief, but finding none. His untouched cock dribbled precome, useless inside its cruel confinement.
Juro let out a whimper as Professor Tok removed the speculum with a filthy slurp.
"First phase of transformation is complete," the alien announced. "The subject’s body has been optimized for breeding - mammary glands primed for milk production, birthing passage expanded and sensitized, and penile orgasms restricted to ensure total devotion to his role as a host. He is ready for insemination."
On some unseen command, the examination table began to shift and reform, rearranging Juro's splayed body into a new position. His legs were folded up and back, knees pressed towards his shoulders, spreading his cheeks wide to expose his raw, pink hole. Stirrups locked around his ankles, holding him open and immobile. His wrists were pinned above his head, leaving his body vulnerable to whatever unspeakable act was about to unfold.
Juro flushed with humiliation at the lewd posture he had been forced into, his most intimate places displayed for alien eyes.
"Please note, this is the optimal position for male human insemination," Professor Tok explained clinically. "It will align his rectum for deep penetration and employs gravity to aid in sperm transport. This will ensure maximum genetic transfer."
One of the students piped up, its voice trembling with barely restrained excitement. "Professor Tok, will we all get to practice inseminating the subject?"
"Of course!" Professor Tok trilled. "This is a hands-on learning experience. You will each take turns mounting and seeding the male, practicing your technique. I will monitor and assess your performance."
The room filled with chitters and growls as Juro's eyes went wide with panic. It had finally sunk in. They were going to fuck him. He'd been trussed up and presented for breeding like an animal. These aliens were going to take turns, coming in him until their twisted experiment was complete. Juro tugged helplessly at his bonds.
Professor Tok rubbed their tentacles together. There had been so many applications that they were able to select the finest representatives of each species.
Now, who should go first . . .