The Mana-Absorbing Orifice
"You put a Magic Stone in there...? And it actually had an effect?"
Shaitan, who rarely ever let her expression waver, stared at Gremory with a face openly twisted in shock and horror. Gremory was trembling, drool and sexual fluids leaking from her mouth as she shuddered. I kept pushing the Medium-Grade Magic Stone deeper with my cock to ensure it wouldn't slip out.
"Yeah. They say it turns into mana the moment it goes in, right? I don't know the specifics, but that's what she said herself. Hnnngh."
"My god."
Shaitan crouched down and placed a hand on Gremory's lower abdomen. Even though my cock was busy reciprocating inside Gremory's depths, Shaitan was fixated on the fact that the Magic Stone had converted into mana within the vagina.
"The mana is truly being absorbed into her body. This... this is practically the same as gaining experience points according to the System."
"Really? Why?"
"For witches and mages like Gremory, the scale of their power depends on how much mana they can store within their bodies."
"Is that so? Heh, looks like I hit the jackpot with this thrust."
I’d just tried it on a whim, but to think it would be a jackpot. I hoisted Gremory up and flipped her over so she could absorb the mana more comfortably.
"Ah, a-ah, too much, it's too much...!"
Gremory was flushed from head to toe, thrashing about in a frenzy. Her voice had loosened up completely, and she was feeling it more intensely than ever before.
"Master, how did you ever discover something like this?"
"I was just thinking about something like anal beads and shoved it in, and the reaction was insane. I never imagined it would absorb mana."
"Hmm... Gremory, if you'll excuse me."
"W-what?! Even you, eek?!"
Shaitan began to gently rub Gremory's clitoris with her index finger. The contrast between the black clitoris and Shaitan's white fingertip was stark.
"I am reading the flow of mana. Please, bear with me for a moment."
"I-I, every time you thrust, I'm forced to, ahhh!"
"For someone saying that, you seem to be enjoying it quite a bit. Hmm... I see. I've figured it out."
Shaitan pulled her hand away from the clitoris and began to rub the underside of my cock back and forth with her palm. She was stimulating the area below my urethra as if demanding I ejaculate immediately, so I adjusted my posture to give Shaitan what she wanted.
"Ready for the mana injection?"
Splurt, splutter. My cock swelled, and in an instant, a massive amount of semen filled Gremory's insides. Gremory couldn't even scream; she just dropped her head and fainted.
"Oh, I see."
Shaitan smiled brightly, wiping the semen that had leaked from Gremory's vagina with her index finger.
"Master's semen melts the Magic Stone!"
"Is that how it usually works?"
"No. It seems Master is quite special."
Shaitan brought over a Lowest-Grade Magic Stone and began to rub my semen onto it. Crackle. The Magic Stone began to lose its form as if its shell were peeling away, and soon it turned into a thick liquid sparkling like starlight.
Lick. Shaitan brought her tongue to it without a moment's hesitation.
"!!"
Shaitan's eyes widened. Her wings and tail stood straight up in surprise, and soon she drank up all the starlight-sparkling liquid with a greediness that could only be described as ravenous.
"Haa, haa."
Shaitan looked up at me with ecstatic eyes. The sticky liquid on her lips sparkled, making her look exactly like she had just finished performing oral sex.
"This... is a revolution."
"A revolution?"
"The mana of the Magic Stone is contained within it perfectly. With this, there's no need to extract mana from stones... nor is there a need to convert stones into life force for forced synthesis."
"What."
It was, quite literally, a shock and horror.
"Is that for real?"
"Why would I lie to you?"
"It's just hard to believe. S-so, let's summarize."
Just as Shaitan was shocked, I was so stunned I felt like I might faint. I set up an experimental plan to verify Shaitan's hypothesis.
Experiment 1. Was this just a one-time coincidence?
"First, let's run experiments until you're absolutely sure. Shaitan, bring me some Low-Grade Magic Stones we got from clearing the sub-dungeons."
"Preparations are complete."
No sooner had she spoken than Shaitan brought over a few Magic Stones she’d had stashed in the warehouse. Compared to the medium-grade ones, they were smaller and looked like nothing more than pretty pebbles.
"Hey, Gremory."
I laid the unconscious Gremory on the bed. She remained in a dead faint, and I pried her crevice open to the left and right.
"I'm putting the stones in."
Gremory didn't answer. Even if she had said no, I would have put them in anyway. Gremory was the woman most optimized for this kind of experiment.
'If things go well, that hole could fit two or three stones at once.'
It seemed Gremory's hard work in the bedroom over the years was finally starting to pay off. In this situation, Gremory's wide hole, which had plenty of space left even after my huge cock entered, even looked beautiful.
"First, experiment number one."
Can she absorb more than one Magic Stone at a time?
I shoved two Low-Grade Magic Stones into Gremory's insides in quick succession.
"......Ugh."
Gremory let out a faint moan and furrowed her brows. Perhaps because the lower-grade stones were more angular, they seemed to scratch her vaginal walls as they went in, causing her pain.
"Shaitan. Pain relief. Pleasure conversion."
"If I do that, the converted pleasure will also decrease."
"It's fine. I felt so much earlier that I need a break."
As soon as Shaitan raised her hand and used Holy Magic, Gremory's expression began to relax. I shoved my fingers deep inside to keep the stones from slipping out, then thrust my cock in.
"Phew...."
Perhaps because I’d been pounding her so many times already, Gremory's vaginal walls were as soft as tofu. I realized why Gremory always insisted on using her clone—I understood it deep down.
'After pounding her this much, it might be better to go for the armpits next time.'
It seemed she needed a lot of time to recover if I went for too long. Nevertheless, I thrust my cock in repeatedly.
Squelch, squelch.
"I'm getting a reaction."
Shaitan pressed her ear against Gremory's lower abdomen and began to move her hand slowly. With her movements as gentle as a healing touch, I had no choice but to slow down my thrusting.
Screeech, fwooo.
Gremory's vaginal walls gripped my cock with great difficulty. Even though she was completely drained of energy, the vaginal pressure she exerted to stimulate my cock was pitifully endearing.
"Shaitan. Is there by any chance a Holy Magic spell that forces ejaculation?"
"Uh... there is a spell that temporarily induces premature ejaculation. Master, that's a bit..."
"Do it."
For the sake of the experiment, and for Gremory's stamina, I decided to make myself prematurely ejaculatory for a while. Shaitan made a tearful face as she reached out toward my cock.
"First, please know this. I want to do it with you for a loooong time."
"You can just make me last long in a dream."
"...Ah!"
Shaitan understood immediately. And the moment I received Shaitan's help, my cock began to ache as if it were about to burst.
"Kgh?!"
There was no way to hold it back. Unlike before, the moment I thought, 'I'll hold it,' my cock was already twitching and spraying semen.
Splurt, splurt.
"Now...!"
Shaitan climbed on top of Gremory and began to stimulate her clitoris with her tongue. Watching her close her eyes and roll the clitoris with her tongue felt like a solemn ritual.
Squelch, squelch.
Gremory's insides accepted all of my semen without any trouble. Her vagina was so wide that it didn't even leak even without me blocking the hole with my glans.
"Hmm, hmm, I see...."
Shaitan pressed her lips to Gremory's lower abdomen and lifted her head. She naturally opened her mouth wide, and without thinking, I shoved my cock into Shaitan's mouth.
"I will clean you up. Slurp, chomp."
Shaitan's tongue wrapped around my cock. And I realized something had gone wrong.
"W-wait a minute!"
I had just ejaculated, and I hadn't even had a moment to feel the afterglow. I grabbed Shaitan's horns to pull her head away, but she set her teeth like an anchor, biting down on my glans, and I couldn't push her off.
[You haven't done it with me lately.]
"No, that's because I was busy... Don't talk through the System! Kgh?!"
Shaitan rolled her eyes up and smiled sweetly. Then, she opened her mouth wide and tilted her head back.
"The first experiment was a success. Regardless of the type of Magic Stone, the stone turned into mana and was absorbed into the body."
Shaitan spun her body around and lay down next to Gremory. Unlike the naked Gremory, Shaitan, who had kept her suit on, pulled her skirt up and raised one leg high.
"This is the second experiment. Does it apply to other subordinates, not just Gremory...?"
"Then can't I just call Ryun?"
"Master."
"Alright, alright."
How could I tell her no when she was grabbing the opportunity she wanted? Especially when it was a woman who was spreading her legs like that, expecting me to fuck her.
"Hold on."
I used the angular part of a Low-Grade Magic Stone to make a hole in the stockings at her crotch. As soon as I made a small hole, I shoved my finger in and spread it left and right.
"Looking at it like this, the comparison is stark."
A dark brown color, worn and used, like an ordinary witch. A pink color, a succubus who is a pro in dreams, but has only been used by me. I felt a bit sorry for shoving a Magic Stone into Shaitan's insides, which hadn't been touched by anyone else's hands, but since Shaitan herself desperately wanted it, there was no helping it.
Squelch, squelch.
"Haaang...."
As soon as I inserted the stone, Shaitan let out a cry and squeezed her legs together. Since she was afraid of feeling pain, I’d already converted it to pleasure, so I could tell the pain of the stone entering her vagina was significant.
"Should I stop?"
"N-no.... The pleasure conversion is stronger than I thought, ugh."
Shaitan bit her lip and tilted her head back. I used the flat side of the Magic Stone to press against Shaitan's vaginal wall and move it.
"I realized something while playing with Shax. No matter how much pleasure there is, if it's repeated and goes beyond a certain point, it becomes painful."
"B-but...!"
"I have no intention of hurting my women. If it hurts, tell me it hurts."
"...Yes."
I sat on Shaitan's legs in the position she wanted. With her raised leg on my shoulder, I slowly pushed my cock into Shaitan's vagina, which was twisted at a 90-degree angle.
"Kgh."
"Slowly."
I pushed my glans in little by little, like a turtle crawling. It was partly because Shaitan was in pain, but also because I felt like I was going to shoot my load immediately due to the premature ejaculation spell.
"Phew, phew."
Even though I’d strengthened my patience, it didn't have much effect. Even though only the glans had entered, Shaitan's vagina tightened so hard it felt like it would crush my glans. The Magic Stone that had gone in before the glans seemed to be quite stimulating.
"Shaitan, let's add a hypothesis to the experiment."
I pushed the glans in just a little more, then grabbed my shaft as if I were masturbating. Shaitan looked up at me with glazed eyes as I stopped moving.
"A-a hypothesis?"
"Yeah. We already figured out that a Magic Stone covered in semen turns into mana. If so... what would the sensation be like to thrust into a vagina filled with semen and melted Magic Stone?"
Tap-tap-tap-tap!!
I shook my hand back and forth faster than ever. It was ironic to be masturbating with only my glans inside a woman's vagina, but this, too, was driving me insane in its own way.
'It feels like I'm using Shaitan like an onahole.'
Even if she's used like an onahole, only I should be allowed to use her. Even the derogatory term 'cock-sleeve' should be an expression only I can use. Setting aside the fact that she's an Incubus or the Demon King's daughter, the woman named Shaitan is entirely mine.
"Shaitan. You are mine."
Mine, someone I can never hand over to anyone else. To leave my mark on Shaitan clearly, I spat out my ejaculation without hesitation.
"I'll fill you up as much as I love you."
"Ugh-aaaah?!"
Shaitan gritted her teeth and shook her whole body.
Fwushhh!!
The semen sprayed from my glans and shot into her vagina. Without even a moment to feel the afterglow of ejaculation, I pushed my still-hard cock inside along with the semen I’d just sprayed.
"Heh, is the experiment a success? Is the Magic Stone melting?"
Squish. Beyond the sticky semen, the soft feeling was definitely not Shaitan's cervix, but the melting Magic Stone. Shaitan's legs fell to the side, and she smiled blankly with a face that had melted like the stone.
"T-the experiment isn't over yet...."
Shaitan staggered and lifted her hips.
"The efficiency of mana absorption while the Magic Stone is melting... and...."
Squelch.
Shaitan used one hand and her tail to spread her anus left and right.
"I-is it possible from the back too...!?"
"Fuck, as much as you want."
I picked up the roundest Magic Stone, coated it generously with the semen on my cock, then shoved it into Shaitan's anus and grabbed her tail to thrust it in.
"Eek?!"
"Thrust it in yourself, kgh. If you're faster than me, I'll fuck you from behind too."
"T-that, hyaang!!"
I thrust my cock in at full speed. The good Shaitan, hoping to be fucked in her back hole as well, buried her face in the pillow, thrusting her tail in like a cock herself.
Thwack-thwack-thwack-thwack!!
"Kyaaaaah...!!"
Shaitan and I had awakened to a new kind of play. Even though the experiment on Magic Stone absorption through the anus ended in failure.
* * *
"I've sprayed like a storm for the first time in a while. Then, slowly... hmm?"
"Ah."
Was it because I had just finished dealing with the hidden boss of the Baphuul Dungeon? Valac, the ill-fated angel who had been suppressed by Baphuul once, opened his eyes and made eye contact with me the moment he woke up.
"T-this is...."
...I made eye contact with him while I was pulling my tail out of the back hole of the fainted Shaitan, wiping away the starlight-mixed semen that leaked out every time she blinked.
"Kyaaaaaaah!!!"
Valac's scream swept through the entire dungeon.