Reisen is in an unfortunate accident after the 'good doctor's' experiment goes wrong and now has a centaur body and a ridiculously big horse cock and balls. 
Sadly Reisen did not warn the doctor that she was in heat and with the addition of her new assets she turns into a burning inferno of hormones, and due to her body structure 
she cannot reach her cock and is stuck in a position of severe uncomfortableness as her balls slowly inflate, overchurning with sperm.
 
Eventually,  veins as thick as her thumbs begin to pop out and throb as blood is jettisoned through them, her horse cock stretches further, gaining a little reddish hue
from the massive amount of blood trying to fill it, her tip leaking a steady stream of pre... But for some reason, no matter how much spurts from her cock, she feels like no
sperm has left her swollen nuts. Left panting and in utter vertigo like she'd been up for weeks, she hears a door open from behind revealing Kaguya, who for some reason was
sporting a pretty good size dog dick accompanied by a hefty sack. Apparently an experiment also went haywire for her, too. But upon laying eyes on Reisen and seeing that huge
throbbing horse dick she went into a primal lust and approached Reisen's horse cock like a moth to a flame.

Where Reisen saw hope of release, her tears of joy were doused by the sudden insertion of Kaguya's dog dick into her tight hole at the tip of her throbbing horse cock, 
Kaguya would make 7 slow thrusts back and forth. Edging deeper and deeper before she suddenly lost her composure and started pistoning in like her dick was on fire. 
Before long her cock knotted inside Reisen's horse dong and she exploded, gallons upon gallons of dog cream ejected from Kaguya and in a strange turn of events began inflating 
Reisen's balls. What was pleasaure for Kaguya, was pure hell to Reisen, her balls got so big the veins themselves streched with the scrotum to compensate the extra weight, 
however, unknown to Reisen, Kaguya had fainted with her knotted dick stuck inside, Reisen tried to buck her hips in hope of much needed stimulation but rather than pleasure
herself it only shook the swollen nuts, causing them to rub against her hind legs, making her yelp in agony from the pleasure, eventually falling unconscious from
the orgasm denial and resulting overstimulation.

Almost as some form of survival tactic, her genitals began secreting a super potent pheromone, so potent that if anyone nearby, no matter the gender,inhaled it they'd be sent
into an incredibly intense rut. Sadly since the room was confined Reisen was trapped in the pheromone dense room to inhale her own wonderful, incredibly powerful musk, 
the sperm in her balls would rapidly become so packed, to the point where Reisen's cum would be 99% sperm, trying to impregnate the foreign sperm and even each-other
out of desperation.

Reisen awoke, in a drunken haze, to Kaguya on the floor. She had been numb to what was happening for only a second before she saw the scene before her. Her balls had grown
to the point where they just barely skimmed the ground, and she could even feel the sperm trying to impregnate the walls of her testicles. The sudden attack of pleasure caused 
her to take a deep breath of the thick, pheromone filled air and she suddenly entered a second, far more intense heat. her cock was throbbing so hard it managed to 
strreetch further and further, with her cockslit gaping like its been abused for days, but only a trail of pre dribbled out, which was coating Kaguya's sleeping form. 
However thanks to the precum coating her, Kaguya eventually arose from her slumber but before she could even take a moment to think she was hit by the pheromones and her dick 
thobbed so hard the veins on it look ready to burst, this time though, Reisen saw an opportunity and as Kaguya was angling her dog dick with Reisen's urethra again,
Reisen lurched forward and somehow knocked Kaguya back, sending a foreign feeling into her brain. Reisen had somehow inserted the tip of her cock into Kaguyas dog dick.


Kaguya, her senses overwhelmed by the pheromones, felt pleasure rather than pain and in her sexual haze went with it, helping to guide Reisen's massive, over-sized horse cock
inside. The veins pulsating on the horse dong's surface were like a pulsating vibrator to Kaguya's dog dick, sadly though what Kaguya couldnt realize due to her hazy state
 from the pheromones, Reisen had been so pent up that the smallest stimulation felt like an hour of sex... it only took one pump not even halfway down for Reisen's horsecock
to unleash its super stuffed payload, as her cock flared it created a perfect seal where nothing could leak out. Kaguya only realized the moment she felt the first
massive spurt. 

Gallons beyond gallons flooded into Kaguya's nuts forcing them to rapidly stretch and groan, this wouldnt be that bad had Reisen not continued to thrust acting like a plunger
to the cum in Kaguya's urethra forcing it into her swollen balls to the point they were spreading her legs....after what seemed like hours, but was actually  just 15 minutes,
Reisen, though still in heat, was sated for now, though Kaguya would need some help later walking since her balls had been stretched to an absurd size on her. Reisen would open
the door to air out the room, and collapse next to Kaguya after such an intense orgasm, little did she know her nuts were already preparing the next batch and her
 cock was only half mast during that encounter, and little did she care she just released that thick, overpowering pheromone-laden air into the rest of Eientei...