Roxy grunted, and came inside Lisa, emptying her heavy balls.

"Okay," Roxy said, panting a little as she pulled her cock out of Lisa's mouth, having managed to not tie her knot inside the foxgirl Familiar's mouth for once. "The baseline we set for my orgasms was... eight mils, thereabouts. Whereas that, with the potency potion... was eighty mils."

"Whoa," Akane said.

"Well, a slight simplification," Roxy said. "That orgasm right there was, to be more precise, seventy eight mils. But! I do think that, as we gather more data points, we'll reach a conclusion that these potency potions multiply our cum output by ten."

"So if we, collectively, made twenty mils per day normally," Nicky said, doing some mental math. "Then it would've taken us fifty days to make one liter of cum, for the leveling of Incubus to 2. But this way, if the potions cause us to make two hundred mils per day, then after today, it should only take four more days to hit Level 2."

"Yeah, that's what I'm thinking," Roxy said, nodding. "I've made some basic orgasm-affecting jewelry with Mystic Artificer, to help make the process more reliable. I did manage to make an enchantment that does the same thing as the potency potion? But uhhhh... they don't stack. And, I've also put, on that same ring, an enchantment that basically milks you dry in one orgasm, rather than spreading it across multiple."

"I don't see a ring," Akane said.

"It's on my finger," Roxy said.

"It's a shame that Akane's the only one who gets to keep the cum-absorption orgasm turned on," Lisa said. "It would be pretty hot if me and Nicky were so goddamn horny and submissive that we came in our pants just from sucking dick, but right now, cum is a finite and useful resource for us, so..."

"Mhm," Roxy said, nodding. "Deeply unfortunate, but... it has to be done. We'll turn it back on once things are stable, but, for this week..."

"We'll survive," Nicky said. "Well, we should head out soon. We've got our delve to do."

"What'll you be doing all day?" Akane asked.

"Doing a delve, myself," Roxy said. "This time, not in a Dungeon eight levels below me or one I made in my basement. Nope, I am delving as close to on-level as a Level 14 can."

"...Wait, what?" Akane asked. "As close to on-level as you can? What, are there not any Level 14 Dungeons you can delve.

"For a variety of complicated, intertwined reasons, Dungeons pretty much only go up to Level 13 in most of the world," Lisa explained. "There exist maybe three Level 14 Dungeon Gates; none of them are natural, and all of them were experimental and are dangerously unstable and unsafe to delve."

"Yeah, exactly," Roxy said. "And that means that there's a soft level cap for everyone at about Level 14. See, it takes around a hundred on-level delves- it varies, from delve to delve, even within the same Dungeon- to level up once. The cumulative XP value of a delve generally goes up by a factor of ten for every level you go up, so therefore, it'd take one delve of a Dungeon two levels higher than you to level up once, ten more delves of that same Dungeon to get on-level with it, and then a hundred delves to get one level higher. But."

"I'm starting to see why this wasn't something they taught us in Basic Training," Nicky said.

"This is very basic math that informs the shape of every delver's career," Roxy said, affronted. "They should have taught you this in Basic Training. Fuck, I'm filing a complaint with the Guild after this... but right now, it's more important that you know that math only holds true up to Level 10. Past that point, it still takes about a hundred on-level delves to level up once, but the factor at which Dungeons give more and more XP goes up from ten to one hundred. If you can delve one level above yours, you can level up from just one Delve. But. That also means that, if you're Level 14 and trying to reach Level 15 by delving a Level 13 Dungeon? That... will take ten thousand delves."

"...Holy shit," Nicky whispered.

"Level 16? Literally one million delves in a Level 13 Dungeon," Roxy said. "Oh, and by the way, the only Level 13 Dungeons anyone knows about? Growth Dungeons, which would be a moderate challenge for a Level 16 party, a dangerous gauntlet for Level 13s, and a long, grueling slugfest for Level 14s. Very, very few people have reached Level 15."

"No wonder you don't seem that interested in delving," Akane said. "But... why are you going back to that kind of grind?"

"Well, for one, I'm pretty popular with my peers as a delver," Roxy said. "I'm a Level 12 Farmer and Alchemist. When I say I brew potions by the barrel, I mean I brew Level 12 potions by the barrel. And I do that because I then have to distill those potions, creating bottles of Level 14 potions. And those, I quite happily supply to my party on a delve, because I very much need them alive and healthy to stay that way myself."

"So... you want to make more friends?" Nicky asked.

"Hm? Oh, no. Right, forgot: two, I'm looking to get a ton of XP so that I can get all my non-combat Classes up to Level 13. Which normally isn't practical until you have a ton of mana to make the sort of contract that would do this sort of thing, but hey, what do you know, I'm a Level 14 Wizard, and I've got a fuckload of mana."

"Ahhhh, so you're exploiting the system to try and skip the grind on Incubus," Akane said.

"Well, no," Roxy said. "Incubus doesn't use XP to level up, it uses semen, so the contract trick won't work. I'm doing this to level up Farmer and Alchemist, which I've been letting languish at Level 12 all this time, but mostly to level up Dungeon Master, which is at Level 1, and will be absolutely miserable to grind up the normal way."

"How so?" Nicky asked.

"For every hundred points of XP people get from your Dungeons, you get one," Roxy said. "It takes a population of, like, four hundred active delvers to make one Dungeon Master level up at a reasonable rate. And good fucking luck getting those! Half the Dungeons on this continent were built by Kara Strong-In-The-Arm, the best Dungeon Master to ever live, and it'll be damn tricky getting that many people to agree to delve your jank-ass dungeons."

"But, the Guild..." Akane said.

"The Guild is still in a period of reform, restructuring, and improvement," Roxy said. "And Ariel Ironborn isn't doing what she's doing just to improve the rate at which her Guild members level up. Ariel Ironborn is very risk-averse, and the mentorship system, in addition to producing higher level delvers faster, is also doing it a lot more safely and reliably. When it comes to Dungeon Masters, she's... a lot more cautious. She's recently rolled out some new safety regulations that let Dungeon Masters and their immediate households delve Dungeons that haven't been tested as thoroughly by the Guild's inspectors, but that's about it, so far." Roxy sighed. "I haven't told you girls why I wanted to be a Dungeon Master, have I?"

"You mentioned wanting to do some research in the field, but..." Akane trailed off.

"That's not the whole," Roxy said, shaking her head. "I want to improve on the infrastructure that Kara Strong-In-The-Arm built. What we've seen from other Dungeon Masters after her, in times of better record-keeping, says that someone like her, at Level 20 Dungeon Master, should have been able to make Dungeons of every Level, not just up to 13. But she... didn't do that. For reasons we don't understand, because she didn't keep a journal herself, or if she did it was lost to us, and also, she's been dead for five hundred years." Roxy sighed. "If I can improve things... If I can get Dungeon Master up to Level 14, with just a hundred delves in that Level 13 Dungeon... and if I really understand Dungeons, better than anyone else who's come before me... I might be able to make a stable Level 14 Dungeon. And that alone would be a big step forward. That alone would let people hit Level 15 in only a hundred delves. And that alone is something worth striving towards."

"It's a lot more doable with a Familiar who has the System Knowledge 2 Trait," Lisa pointed out.

"...The fucking what now."

"System Knowledge is a Trait that monstergirls can have," Lisa said. "With Familiars, it's capped at the level of knowledge attained by the living sages and scholars in their bondmate's community. So, y'know. Only gotta get Dungeon Master up to Level 13, make a Level 13 Dungeon that isn't a fucking Growth Dungeon, and then you'll have people lining up for miles to suck your dick for a chance at the first Level 13 Dungeon that's not a brutal, unrewarding slog."

Roxy stood there silently, processing all that.

"Well shit, I might as well amend my contract with my party," Roxy said. "Fuck me running... Thanks, Lisa. Well, here's hoping that, by the time I'm through, we can upgrade your System Knowledge Trait to 3."

"Of course, that'll just mean there's more work for you to do to upend the current dynamic," Lisa said. "System Knowledge is comprehensive, after all, and you're going to mostly be studying Dungeons. I'll learn some things you haven't, and then we can work out a way to use all that."

"Wouldn't that be nice... Right, well, I need to get to Venompit soon. You three probably have a delve to get to, too. See y'all tonight."

"Bye!"

---

"Alright," Roxy said, rubbing her hands together as she disappeared the clothes off her body. "Day 5. We're one orgy away from Level 2 of Incubus. I'm excited, and not just because I'm about to have sex."

"Honestly, as nice as the sex is, it's kinda stopped being special," Akane said. "We do it every day, and we've lived together for almost two months now. It's just... y'know. It's not special anymore. I still want to do the daily sex thing, but... I mean, it's not really exciting anymore, is it?"

"Hrm, point," Roxy said. "Well, whatever. We can consult some magazines or whatever for those 'spice up your sex life with these weird tips' articles, and try whatever doesn't look heinously stupid."

"We could also just... cool our jets, and not do daily sex as a rote ritual where we go through the motions," Lisa pointed out. "...But, like, after Roxy gets Incubus leveled up."

"Exercise self-control?" Nicky asked, incredulous. "Lisa, we're women in our twenties. You might as well ask us to fly you to the moon."

"Honestly," Roxy said, "I'm kinda having more fun with the conversations we have before, during, and after the act than I do with the act itself. Like, yeah, it's nice to cuddle up with a curvy girl at the end of a long day, but... Iunno. It's not actually exciting or interesting to me anymore either. I just, uh. Didn't want it to seem like I was losing interest in y'all."

"We are still going to fuck, right?" Akane asked.

"Probably," Roxy said. "I mean, we do need to harvest the cum for Incubus, but... Hrm. Y'know what, let's do something mildly novel. Everyone lays back, and one by one, Akane sucks us off. Try not to knot yourself."

"Works for me," Akane said, shrugging. "You wanna go first, Roxy?"

"Sure, why not," Roxy said, laying back on the bed. "Nicky, Lisa, wanna cuddle while you wait for your turns?"

"Cuddles are always nice," Lisa said.

"I think the problem might be a matter of why we're having sex," Nicky said, even as she cuddled up to Roxy's side.

"What do you mean?" Roxy asked, as Akane began to suck her dick.

"It feels obligatory and like a chore because, now, it is," Nicky said. "The Incubus class, while ostensibly a very sexy thing that incentivizes having a lot of sex, has now tied sex to extrinsic rewards, which takes away from the intrinsic rewards of having sex- some light exercise and intimate socialization with others."

"Hrm, fair enough," Roxy said, even as Akane fit Roxy's entire cock up to the hilt down her throat. "Maybe Lisa's right, and we should cool our jets after this. I'm an Alchemist, I can give y'all something to preserve organic liquids in, no problem. Just... Y'know." She moved a hand around Nicky's shoulders, then down to grab one of Nicky's boobs. "Jerk off once a day, and then, maybe once a week or so, when the mood is right, then we fuck. Preserve some of the magic, now that sex isn't our overly-optimized cum harvesting method."

"That does sound nice," Nicky mused as Roxy approached her climax.

"Personally, I think doing a cum cascade like we did two nights ago would be nice," Lisa said. "Y'know, that thing where Roxy was fucking Nicky and Nicky was fucking me and I was fucking Akane, and none of us were able to cum unless someone came in us first? God, that was amazing. Oh, hey Akane. Done with Roxy? Mind doing me next? Thanks, doll. But yeah, something like that would be fun."

"It would, but..." Roxy yawned. "Fuck, I am tired after today's delve. Level 13 Growth Dungeons are exhausting."

"Maybe we should speed things up and go to sleep?" Nicky suggested.

"Probably," Roxy admitted, before turning to look at Lisa. "[Orgasm.]"

Lisa came immediately, and Nicky didn't even need the spell to do the same on her turn.

"Alright, I have finally hit... Level 2..." Roxy said. "Of Incubus. Fuck I'm worn out... Okay. Well. Incubus Level 3 calls for ten liters of cum, so. Uh. Guys, I think we've reached the limit of what potency potions and enchanted rings can practically do for us."

"What the hell else are we going to do, though?" Nicky asked. "What other options do we have?"

"There is something unorthodox we could do," Lisa said. "Roxy is a Level 13 Dungeon Master now. She can definitely make some exotic sorts of Dungeons. There's a sort of Dungeon that'd solve this problem... plus, it'd also solve that other problem we were complaining about earlier."

"You don't mean," Roxy began.

"I do," Lisa said.

"Spill the beans," Nicky said. "What sort of Dungeon is it?"

"The Dungeon that'll solve all our problems," Lisa said. "...well, two of our problems... is the Sex Dungeon."