A Beast Class Servant being summoned was supposed to be impossible and therefore, it was something that had to be studied. At least, that was as far as Gudao had understood the underlying reasons and explanations for why this was happening; all he really cared about was that Draco wasn’t causing issues around Chaldea and that she helped out in the fight and beyond that, who and what she was didn’t really matter.
 
DaVinci, among others, had insisted that at least some tests had to be run for the sake of establishing the technical details of the Class in question for a variety of reasons that pretty much flew over his head. Every Beast so far was almost wildly different, after all, and some of the tests just didn’t seem to have any combat implications, if that even was the planned end goal…
 
Today though, Draco was facing the last batch of tests and he was to accompany her. She had grown quite attached to him, and quite bored with the tests they were running, so she had begun to insist that he accompany her whenever DaVinci needed to run the tests in question or else she would be, as some put it, even more insufferable than she normally was.
 
Of course, as Gudao had more than gotten used to Nero’s antics, especially with three of them already roaming Chaldea before Draco, all he really saw was a smug dragon girl who insisted he hold her hand as they walked through the hallways toward DaVinci’s test site, and who would pout if he refused. It was actually rather cute when put like that, not that he would actually verbalize it if he can help it.
 
“Oh, Melusine. Did you need something?” Gudao asked, seeing that the other girl was walking in the opposite direction, her eyes glued on Draco and Gudao’s locked-together hands for a moment before trying to glare a hole through the Beast and giving Gudao a certain sort of look.
 
“No, I just… Happened to be here.” She answered, though he knew that she was lying. Ever since Melusine was summoned, she had a tendency to try and be around him as well, less demandingly so than Draco, but still trying to accomplish it and further reinforce it by sneaking into his bed at seemingly random intervals.
 
“You can happen to be elsewhere as well.” Draco mockingly interjected, which only further drew Melusine’s ire.
 
“Melusine…” He had to dispel the situation before a fight breaks out. “We can spend some time together after DaVinci’s done with her tests, if you’d like?”
 
It really was more or less as simple as that. Melusine smiled again—some movement under her skirt just barely being caught by him—while Draco went back to a small pout. Melusine was happy and smug enough to simply continue and move on happily, while Draco was too prideful to make demands immediately, even if Gudao knew that he would have to pay for it sooner or later or she’d stay upset.
 
For the time being though, aside from squeezing his hand harder as punishment, Draco didn’t make any demands and simply followed along to finish off the tests that DaVinci was insisting on, clearly wanting to be over and done with that whole thing far more than wanting immediate retribution.
 
o.O.o.O.o
 
Thanks to prior testing, DaVinci seemed to have gotten a hang of how to handle Draco as well, going over previous test results even if Gudao was just barely listening and putting them in a way that praised Draco to hopefully get her in a good enough mood to go through with what was required of her.
 
“And with all of that… This time, we’ll be testing your reproductive abilities.” That certainly got Gudao’s attention. “Normally, Heroic Spirits don’t really have much in the way of those, for various reasons, but you’re an exception, as was established multiple times over, so it’s worth checking to make sure. So! Please, get naked.”
 
“I refuse.” Draco responded simply, not even entertaining the idea in spite of DaVinci’s attempts and much to her annoyance. “Unless he goes through the same tests as me.”
 
“Huh?” Gudao voiced his surprise while DaVinci’s mind went racing at high speeds to connect and compare dots, make theories and theses and so on.
 
“Well, I suppose it’s not impossible…” With which DaVinci meant a lot of things. There were certain preparations she had made with Draco in mind, which might make things a bit odd for him if she was right, but the functions should remain ultimately the same, in spite of certain expected parameters that might make things a bit strange. “The information and pictures might also help refill our Saint Quartz reserves…”
 
“What was that?”
 
“Nothing!” Clearly, she hadn’t intended to say that last part out loud. “Well? What are you waiting for? Start stripping!”
 
He certainly would have questioned if he gets an actual choice in this, but he already knew that he didn’t; this was probably payback for Melusine as well, even if he hadn’t expected it to come so soon. As such, all he could do was start taking off his uniform, not really putting any effort into making it explicitly sexual even if both Draco’s and DaVinci’s eyes were pretty much locked on him and certain prior experiences told him he should at least put a bit of effort into it.
 
Thankfully, getting his clothes off was a quick process, and he already knew, more or less, what to expect as he had already been made to go through the process back when he was still just a fresh recruit. Though most of his body had gone through changes one might expect after all the fights and exercise he had been forced through, certain parts of his body simply didn’t change no matter what, at least as far as he was aware.
 
As he stood there fully naked though, Draco started to hold up her end of the deal as well, quickly getting rid of what little clothes she wore… Which allowed him to focus on a particular part of her crotch. While there were certainly a number of jokes that someone else might have made in regards to the dark void that seemed to be centered there, this time it was a literal mass of magic and curses as far as he could tell.
 
And it was undone with next to no effort from Draco, revealing its purpose. It only made sense for it to be there, considering her usual choice of clothes as her dresses would be entirely helpless in trying to contain the sheer mass and presence that was unsealed.
 
Each of the massive balls seemed to be the size of a baby’s head, if not larger, as they just barely defied gravity to prevent themselves from hanging as low as objects that heavy should have hung; between and over them was something that could only be described as a second tail as well.
 
It wasn’t a tail though… In spite of having the occasional scale along its length, mostly focused around its base, it was, without a doubt, a massive, menacing, cock that grabbed so much of his attention that he was barely able to notice her closing in on him and snuggling against the side of his body as if to further claim her territory; against his leg like this, even soft, he could tell that it must be thicker than any of his limbs.
 
“Great! Let’s get started, then.” With a happy step and suspicious intonation to her own tone, DaVinci proceeded to lead them toward the first machine, giving a quick explanation that it was supposed to measure their cocks… Individually, of course.
 
The fact they were clearly supposed to be doing it one at a time however did not prevent the suggestive moments from Draco as she used her actual tail to guide her cock up to and against Gudao’s own, thrusting up against him to start frotting and getting him fully erect before either he or DaVinci were able to correct the idea.
 
“Oh, I know.” Draco happily stated before pulling back and allowing him to go first, even throwing in a mocking slap on his bare ass to encourage him with lust in her eyes.
 
His measurement was over quickly and easily, almost embarrassingly so and producing almost the same results as last time. He was a bit closer to eight inches in length than last time, half of that in girth and closer to the one hundred and fifty gram mark, but it wasn’t much of an improvement, even if the sheer fact he did go through some increases almost sparked some amount of male pride in him.
 
A pride that was almost immediately squashed as Draco flopped her soft cock in his general direction. In spite of the sheer sadistic, dominating, seduction in her eyes, she was still more or less as soft as she had been when she first stripped. “Would you mind giving me a hand with this?”
 
Naturally, Gudao first looked to DaVinci for guidance… But she was going through something as well, if the look on her face was any indication. She had clearly expected and planned for Draco’s equipment, but even she seemed to be mesmerized by its actual presence, even slightly concerned and just barely hiding it well. She wouldn’t be of much help with this anyway, as Gudao knew he had to do it himself.
 
Though the rest of her cock was soft, the scales that decorated it were still hard, as one might expect and he found his hands almost gravitating toward them as he tried to wrap his hands around the full girth. It was manageable at first, the soft and warm flesh of her cock indenting somewhat and allowing his fingers to sink into it, but as he started to jerk her off, it became increasingly difficult to keep it up.
 
Gudao slowly had to move out of the way as the behemoth of a cock got harder and closer to his face and body, slowly leaking precum that he diligently collected and used to help lubricate the expanding length, allowing him to jerk her off even more efficiently. He quickly had to give up the attempt to wrap his hands around it as well, instead keeping one hand near the base and almost stroking her scales, which still sparked responses from her, while the other went along the length and occasionally rubbed the head.
 
As the goal, thankfully, was not to make her cum on his own, Gudao only had to continue it for so long before it stopped growing. The sheer effort he had to put into it, alongside the almost suffocating musk, still left him winded though, the heaviness of his breath only intensifying as he was left face to shaft, slowly getting up even if Draco was still thrusting demandingly and leaving small kisses of precum along his body.
 
With a click of her tongue, Draco held her cock and took it to be measured… Regardless of if it truly was at full mast or not, even this much caused the machine to fail a few times, forcing it to self-reset around her and just barely managing to give out values before breaking down entirely. Well, at least Gudao assumed it broke down, considering the smoke and sparks that started to come out of it.
 
“…Wow.” DaVinci sounded genuinely impressed as well, even before they read out the values together. Just over two and a half feet long, a girth of just under ten inches and a weight of sixty-five kilograms, which, as DaVinci further noted, matched the weight of her actual tail.
 
“That’s enough for today.” Draco declared on her own, her tail wrapping around her cock again, stroking herself rather openly.
 
“What? No! We’re not done yet! There is still the semen output test!” DaVinci insisted with the upsetness of someone who was having a work of art threatened with repossession.
 
“Oh? Bold, for someone of your stature.”
 
“A-Ah… No, it’s supposed to be done by using that breeding mount over there…” Though, faced with the actual size of the cock, and the results of the previous test, DaVinci was considerably less convinced in its ability to handle and perform the job it was made to do…
 
Draco must have known as much as well, regarding the machine with an unimpressed look, her tail letting go of her cock and wrapping around Gudao’s leg, making him flinch a little as the sensation ran up the length of his body. “Well, we are done.”
 
Matching her declaration, the tail, slick and carrying a slight wetness from her cock, was fully wrapped around Gudao’s leg, holding on to it possessively with it scales rubbing against his cock and balls, gradually stimulating him and preventing him from going soft either, her cock bouncing and tail jerking his leg off to rub her essence even harder and deeper into his skin.
 
Gudao swallowed heavily. She certainly knew how to drive a hard bargain, but right now, he had to go along with it or she was just going to cause even more problems the next time around. “Come on, Draco… Let’s just finish this, and I’ll do whatever you want later.”
 
“Hm? Yes, that does sound acceptable… Very well, you may go first.” Her tail unwrapped from his leg painfully slowly, giving a long stroke against his balls until the very tip of her tail passed by to offer a final wave-tickle.
 
o.O.o.O.o
 
Under the careful gaze of Draco and DaVinci, Gudao ended up needing just over ten minutes to finally cum, scoring a final result of four milliliters and a density of eighty m/ml, which was stored away in the machine for later archiving and tests. After that, the machine was adjusted for Draco as best as it could be. Of course, the most they could do was loosen it a little so as not to cut off circulation, and lower it down to her height…
 
Though she had kept herself hard as best as she could be bothered, she didn’t really put much effort in fucking the mount. The minutes ticked by with barely even an additional grunt of effort from the Beast, showing no sign of being worn down no matter how much she thrust into the mount. Even this was noted by DaVinci, but before long, the novelty wore off and it just became an exercise in frustration for everyone involved.
 
That was, at least, until DaVinci managed to convince Gudao to climb on top of the mount and “sit there sexily”, as she put it. Not that he really knew how to accomplish it, but like with every other impossible task that was put in front of him, he did his best to accomplish it.
 
To his surprise, simply sitting there and doing his best to give encouraging words to Draco seemed to be enough for her thrusts to slowly grow more wild. Even without the breeding mount changing in any way, just looking at him and thrusting below his body like this was enough for things to slowly change and, within a few minutes, she started to cum.
 
And she kept on cumming. DaVinci panicked slightly and rushed over to the machine as its storage capacity was overwhelmed, but even as she tried to make some emergency changes, the situation quickly proved to be too much. Draco simply continued to grip the mount with her hand, her hips jerking a few more times as sludge-like cum flooded the machine and gradually started to go beyond.
 
The most DaVinci found herself capable of doing was make some final observations before it all broke apart. The volume was simply incalculable, the density reading as eleven b/ml. The cum seemed to even have a collective mind of its own as well, seemingly specifically targeting and flooding over Gudao’s own cum, not only overpowering it in sheer quantity, but literally attacking it as well, eating it as if it was a natural predator.
 
The chance for further further notes vanished however, as the storage tanks broke apart, carrying DaVinci off as the compressed cum burst out like a targeted stream, quickly starting to flood the nearby corner of the lab as Draco just kept cumming, either ignorant or uncaring of the destruction she was causing.
 
Gudao was more than a little concerned, watching Draco’s hips eventually stop moving, as well as the flood of biblical proportions that seemed to be trying to drown DaVinci, the lab or both, if not simply bury them. The sheer density of the cum left it slow moving, crawling in a way he could only compare to the movement of lava from a fresh eruption—Perhaps he was just imagining it, but now that he was focused on it like this, he almost felt as if it was literally radiating heat as well.
 
The intended experiment almost certainly failed, but as he swallowed thickly, he couldn’t help but not want to be here anymore, prompting his body to start trying to dismount the broken machine he was still sat upon.
 
“And where do you think you’re going?”
 
He didn’t get far before his leg was grabbed by Draco though, swiftly finding himself pinned under her overwhelming mass. The cock was placed directly above him, laid on top of him with just enough hardness to still be massive, yet soft enough to weigh down with a heavy, crushing, force applied to his own cock, balls and even stomach.
 
“Draco—"
 
“You promised, didn’t you?” She cut him off with a glare that was more lustful than wrathful, but still just as strong in silencing him for long enough for her to pull back, aligning their cocks until he felt what could only be the opening of her urethra, as well as everything still inside it, against his reinvigorated cock.
 
Gudao squirmed as Draco simply thrust forward, impaling herself on his cock with enough force she pushed half of his length into her own with the first thrust alone. It was warm, wet in a way that fresh pussy simply wasn’t, and he felt as if the very tip of her cock was applying pressure to his own, massaging and playing with it now that it was inside her like this. Even Draco seemed to have some problems with keeping a straight face in these circumstances, her face twisting in pleasure without a hint of pain.
 
He tried to say something, but all that came out of his mouth were half-moans as she continued to thrust, slowly and carefully as if she suddenly learned what pacing was. Her cock did not agree with the sentiment quite as much however, still applying a lot of pressure on his own, as if it was trying to crush it, as if the last of the cum that remained inside her cock, was trying to clear out his cock inside and out.
 
His mind slowly felt like it started to melt and break apart at the edges at the sudden overstimulation as he grabbed on to the ruined remains of the machine to try and keep himself focused on reality in spite of the situation.
 
The feeling was crushing and overwhelming in all sorts of ways, strange sensations of fullness and motion around and inside his cock leaving him feeling like he was being stuffed only so she has something to actually break apart and crush into nothingness. There was certainly something there, but the depravity, the fullness, the texture, only kept growing for her entertainment at the slowly increasing cost of his sanity and cock.
 
There was no protection or defense for his sake as she came once again, the massive deluge of cum rushing up his urethra with overwhelming force, the warm intrusion reaching deep into his balls, filling them up faster than the territorial dragon cum could empty them again, replacing everything within them with itself. To an extent, the cum even found its way up his bladder, eliminating its contents as well before it found itself with truly no more space to fill.
 
The pressure only further built from there, the cum unable to occupy any more space being pushed against and pressurized against the still remaining Beastly levels of the same, trying to accomplish an impossible task. Pressurized cum shot out around the edges of Draco’s urethra as a result, further dirtying the untouched corners of the lab and trying to paint, to mark, Gudao in its colors.
 
Compared to the one that broke all measurements, this orgasm was shorter, Draco pulling back faster than before and revealing the results—her cock twitched a few more times, the cum shooting out with enough pressure to dent the material of the ruined machine but neither of them could really focus on that.
 
Though exact measurements would need to be retaken and confirmed, they could both tell that Gudao’s cock was half its prior size. Painfully hard, the tip of it looking more compressed than before, tighter and borderline sealed with no exit, but still half the size it had been before the relentless assault.
 
Even that, however, proved to be of little concern to the Beast as her breath continued on heavily, her eyes just as full of lust, if not even fuller while her cock carried absolute wrath. Gudao didn’t even know what he should, or even what he could, say in this situation, simply recognizing that the Beast of Humanity in front of him was too far gone for simple negotiations.
 
Even feeling that danger was fast approaching, there was nothing he could do as she grabbed his legs. His mind was still recovering, his focus unable to acknowledge anything but imminent danger and the addicting, mind-melting, smell of depravity, of the cum that covered his chest and stuck all the way up against his chin, refusing to fully run down like some mere watery liquid.
 
The only one who could help him was currently busy as well, DaVinci simply watching there, masturbating to the scene in a way that pushed the discarded cum into herself, her eyes distant and yet locked onto observing the situation that he was a bit too numb to fully acknowledge himself.
 
He had barely been able to tell that Draco had taken his legs and shoved them down the opening of her cockhole. As he had searched for answers to a danger he was only aware of the imminent arrival of, the danger had rather clearly defined itself and begun to consume him. His legs vanished with hungry gulps by the massive cock, a continued squishing noise sounding out in place of throaty gulps as his limbs were pushed up against the cum still trapped inside along with him.
 
In spite of the state of his cock, he was still able to quite clearly feel it when her own started to crushingly engulf his balls, pressing up against the base of his cock while indelicately bathing his scrotum in the warm fleshiness of her insides, pushing up his comparably insignificant phallus against his pelvic region.
 
It only lasted for a few moments however, before his cock was consumed again and he fought against the need to moan at the sensation. Instead, he begged, struggling against the weight of words in his throat and burdened mind to beg her to stop. She did not listen, even going as far as to put a hand over his mouth and one against his chest, digging her fingers up close against his collarbone.
 
He was hers and she was proving it. She was marking him, while consuming him in his entirety, while thrusting with increasing force to work her way up his torso. Her fingers trailed around his head, capturing her cum before going into his mouth, giving him an early taste as her cock devoured past his elbows and hips.
 
His body was forced to contort from the pressure in her balls, most of it still held in place by the tightness of her cock while his legs bent as best as they could to make proper space for him to slide into. He could feel the heat, the sludge of her cum, the tightness of the space she wanted to put him in, where he did not belong and yet she insisted on his place.
 
Chest, upper arms, shoulders, neck… She gave his face a final lick with a movement that nearly could have had her sucking herself off before his head started to bend upwards to stay out for as long as possible. The slides of her slit closed evenly around his face, leaving only his nose for the briefest of moments before that too was forced downward, vanishing him entirely from the outside world.
 
Barely still awake and aware of himself when faced with the overwhelming authority of the Beast, the constant stimulation against his nerves, some of which he hadn’t even truly been aware of before all of this, Gudao found himself surprised he had managed to make it in one piece inside her balls.
 
Most of the old cum in her urethra had been dragged down by the rest of his body before it, leaving his face simply moving through the almost clean but still moist insides of her cock, all the way until he fully passed through the length and was unceremoniously dumped inside her balls with the rest of his body, the reserve of cum easily at drowning level with nothing to hold on to.
 
He tried to push out and against the situation, but the consistency of her cum simply immobilized him, making every movement painfully difficult. He was not strong enough to push against it, yet it parted only for him to go further inside. He wasn’t even sure if he could reach the outer limits of her balls, his arms and legs simply trapped as if trying to preserve him in as weird a position as possible, just barely malleable enough not to break any bones but still strain muscle and prevent his limbs from returning to his side.
 
The cum remained willful and territorial through it all as well. Now that he was fully inside, it took to making sure that it was inside and out as well, invading every one of his orifices with merciless intent, replacing what liquids could be replaced, and filling some places that shouldn’t be filled with a liquid like that.
 
Drowning, suffocating, his lungs, ears and nose filled with sludge-like cum that wiggled aggressively along his own digestion track, he knew that he would not survive this. It was hot, simmering his body, cooking him from all sorts of directions, threatening him with dehydration while refilling him with cum, trying to turn him into just another load, just another part of itself.
 
He started to believe that that was his ultimate, his only, fate at this point, to be killed by the love of a crazed Beast that everyone had warned him about, yet who he chose to trust in spite of all the warnings…
 
—Yet, before it got that far, his grave shook. Even through this impossibly thick cum, he could feel reverberating shockwaves carrying through the viscous material, going around and up the seemingly bottomless expanse to start pushing him up. Filled as he was with it, he could feel the wrath of the cum at being denied like this, but it was only met with more shockwaves until he felt himself, disoriented, carried somewhere.
 
Something grabbed on to him, carrying him out the last distance, pulling him out of the dragon prison with an even more impossible speed. Disorientation followed, then the gradual attempt at return of self-identity, followed by even more confusing events that he could not truly explain even as he suddenly found himself being held like a princess by a presence he recognized as Melusine, her face decorated with a smile.
 
“To think that you’re that much of a masochist that you’d cum from having your balls abused like this.” The smile was barely broken as Melusine taunted Draco and moved again.
 
Melusine, as Gudao quickly noted, was in a strange sort of semi-transformation. While most of her outfit was untouched, cum stained by a considerable amount, her legs were decidedly draconic, clawed, covered in her own scales and one foot pushing against his former prison with a clearly dangerous amount of force.
 
Draco was absolutely furious at her fellow dragoness, and for good reason. She was hunched over slightly, a few light scratches on her balls, one or two of which were actually bleeding while the rest of the massive expanse was showing a redness and other signs of utter abuse that could only be called sadistic.
 
But, then, Draco smirked. “To think that you wouldn’t notice you’ve lost.”
 
At those words, Melusine and Gudao both focused on where Draco was looking. His Command Seals had changed their pattern, changed into that of a red dragon with enough obvious and shared features for Draco to call it a sign of ownership even as the Beast had to shift around slightly, wincing at the pain that she was denied the true ultimate victory with.
 
The look on Melusine’s face as the gentle, knightly, smile was replaced with an icy cold gaze that just might be able to freeze hell itself almost made it worth it. Though Gudao clearly wanted to say something, only to end up puking a considerable amount of cum instead as soon as he opened his mouth, definitely pushed it a bit further along the “worth it” scale for Draco.
 
 
Either way, neither of the dragonesses were going to let the other live it down any time soon.