The Great Rimuru was not allowed to visit elf brothels after a series of incidents that ended with Shuna threatening him. That meant Shion had more time for him, and Shion's desire to be close to Rimuru had been getting more intense. As the daily tasks in keeping the city alive grew, Shion was building up more and more stress. So she turned to Rimuru for her release, and he was more than happy to provide. Of all of Rimuru's inner circle, Shion was by far the bustiest. Though Rimuru no longer had his dick from his previous life, his lust for huge boobs remained unabated.
When Rimuru rested under Shion's boobs, using himself as a pillow for her enormous chest, he would occasionally sprout a slimy tentacle, using it to pull her top down and expose her nipples. Shion had a great pair of nipples. They were dark pink, with wide areolae and perky tips. The edges of her areolae peeked through her business suit almost all the time, and while her tips were mostly exposed to him, everyone had some idea of where her nipples were located and what they looked like. After exposing her nipples, Rimuru would press his warm slime against them, and start sucking.
Shion loved having her breasts played with. Rimuru's slime was just the right temperature, and the way it felt against her breasts was comfortable, making her nipples achingly hard but soothing them at the same time. He would occasionally weave his slime through her cleavage, squeezing and coiling it around her breasts before letting them pop back into their normal perky shape. Soon, Shion's nipples began getting hard before Rimuru even touched her breasts.
One day, Shion was alone in her room with Rimuru. She had told the others not to disturb her, but also that she would be done in about an hour. With the doors closed, Shion allowed herself to be naked in front of Rimuru. She removed her business suit, her breasts bouncing free and immediately succumbing to gravity. They jiggled into place, her hard nipples already dripping with beads of sweat in front of the leader of their fair city. Shion pushed her hands under her breasts, raising them and presenting them before the slime she admired as a lover and as sort of a deity.
"Great Rimuru, my breasts have been feeling even hotter and my nipples have been sore lately," said Shion. "I need your soothing slime to suckle at my tits. Let's get started!"
"I do love your boobs, Shion, but we shouldn't rush things," said Rimuru. "Sucking them slowly and gently is better than doing it like a cattle milking machine."
"You can be as rough with me as you want, Great Rimuru," said Shion. "We ogres can take quite a lot. Our bodies are tough!"
"Yeah, but you're not invincible," said Rimuru. "And this isn't battle, this is just having sex. Even a slime needs to spread itself through the world. And I'd be glad to spread myself all over your body."
Rimuru created two tentacles from his side. The blue, slimy appendages moved towards Shion's breasts. Rimuru pulled himself up by one of them, sticking his slime form close to Shion's boob while the other tentacle sucked on her other nipple. Shion moaned shamelessly, her voice so loud it could be heard from outside her room. Rimuru started sucking and tugging at her nipples as he always did, but something was different this time. Something white and sticky was coming out of the pores in Shion's areolae. Rimuru consulted the Great Sage.
It was breast milk. Nourishment for babies and usually only produced in women who are pregnant. The Great Sage surmised that playing with Shion's breasts so much had caused her to start producing milk in those massive funbags of hers, which was now leaking out from the slightest stimulation. Shion's milk was sweet and thick, with the consistency of cream. Rimuru saw some of it settle in his body as he drank it down, a splotch of white against the sky blue that made up his slime body. It was delicious. There were no effects granted from it other than giving him some more stamina and a closer bond with Shion. But the arousal levels were off the charts.
"Shion! You're lactating!" said Rimuru. "Did one of the other ogres knock you up?"
"What? No. You're the only man I'd open my legs for, Great Rimuru," said Shion. "What do you think I am, some kind of common prostitute?" Rimuru looked between her legs at her bushy purple pubes, every one of those hairs trapping the scents between her legs and making her entire body smell that much sexier. "My milk only exists for you. Drink me dry, Great Rimuru!"
"With a pair of boobs like these, gladly!" Rimuru said.
Rimuru sucked hard on Shion's boobs, drawing out more milk. It started as a few drops, before turning into fountains of white milk. It sprayed over Rimuru's body, being absorbed into his slimy being. The milk inside him grew, being added to his body. Shion moaned, delighting at the sticky feeling of Rimuru's body brushing against her heavy breasts, forcing her milk to heavily flow from her nipples. Each squirt of milk made her pussy wetter, turning her on. The sensation of Rimuru, who was like living lube, spread down her body, making her asshole twitch and her clitoris get hard.
Shion embraced Rimuru from behind, pushing him closer towards her breasts. Rimuru sucked harder at her milk, gulping it down with a temporary mouth. The more he sucked, the harder Shion's milk flowed. Every drop from her nipples was a release of sweet nectar, overfilling the HP bar on his stats and making him overcome with a desire to reproduce. Not as a human, but as a slime. That was the form Shion treasured him in, and he wanted to show his love for her.
Watching her milk flow into Rimuru's body made Shion pant heavily, her breath making condensation on Rimuru. She was giving a part of her into him, so that no matter where Rimuru went, he would always have a memory of Shion's naked body. Anything to make the leader of their great nation stronger. She wanted to give him even more if she could. No matter what Rimuru wanted her to do with him, she would provide. After a few more minutes of sucking, the heaviness in her breasts began to drop, followed by the last few drops of milk falling against Rimuru's head.
"You were producing a lot of milk," said Rimuru.
"I won't stop producing unless you stop sucking," said Shion, "We're going to need to do this even more."
"Shion, looking at you naked, it makes me wonder what it would be like if you really did get pregnant," said Rimuru. "All of that breast milk is being converted into magicules inside me, but I can make all sorts of things with this body. Since you gave part of yourself to me, I want to give some of myself to you in return."
"Pick any hole you like," said Shion.
Shion raised her ass in the air, placing one hand on her pussy and the other on her butt, spreading each of her holes apart. Rimuru had a clear look inside her snatch and her anus, contemplating which of the two would be more fun to do first. Shion's pussy was perky and pink, her virginity still intact. She had been saving it for Rimuru, and it was dripping wet. Her folds looked tantalizing to slide across, her womb puckering open and ready to be impregnated.
On the other hand, her asshole had a more taboo feeling to it. It was tight and hot, and to support her big boobs, Shion had an equally big ass. A perfect pair of round, white moons. The smell coming from her ass was slightly worse, but not enough to override Rimuru's love of the female ass. Unable to decide, the slime simply went with both. He crawled up Shion's legs onto her ass, sliding one slimy tentacle into her asshole. He was already wet and slippery enough, squeaking past her tight butthole with ease. His other tentacle extended into her pussy, being nearly the same temperature as her insides. Once he was comfortably settled inside, Rimuru pumped both of them up to be a little thicker.
"Great Rimuru, you're inside my vagina and my anus at the same time," said Shion, blushing madly in love. "My entire body is yours!"
As Rimuru slid his slimy tentacle further into her butthole, he found some of Shion's waste that she hadn't expelled yet. It was bitter and earthy tasting, but absorbing it into his body wasn't nearly as much of a problem as it would've been if he was fully human. It was as if he had given Shion a slime enema, emptying her bowels solely for him as he plunged through them. He had gone as deep as he could go.
"Shion! It's amazingly warm and sticky inside you," said Rimuru. "Getting to experience the warmth of your pussy and the tightness of your ass at the same time makes me glad I'm a slime. Your entire body is amazing!"
"Go as rough as you want on me, Great Rimuru," said Shion.
Rimuru started alternately pumping in and out of Shion's pussy and ass. He slid out slowly from one before plunging into the other, alternating his rhythm. Beads of sweat from Shion's body were absorbed into his slimy form, giving him more power to push through as the sweat that came from between her milky boobs and her armpits became part of him. He changed the consistency of his slime tentacles inside her, making them as hard as a silicone sex toy from back in his own world. He freely changed them, adding bumps and grooves that made them feel even better against Shion's holes.
Shion felt his slimy body resting comfortably on her plump ass. With each thrust of his tentacles, her boobs shook back and forth, spraying out more squirts of milk onto the floor of her room. Rimuru looked past her ass at her wobbling breasts, his two tentacles getting even thicker inside Shion. She was moaning like an animal in heat, completely surrendering her body to Rimuru. The fleshy slapping sound her tits made as they hit against her torso was music to Rimuru's ears.
"Shion! You're so sexy!" Rimuru said.
"Thank you for praising me," Shion said. "To have my holes filled by your magnificent slime dicks is the greatest gift you could have given me."
Praising Shion had only made her hornier. Her pussy sucked him in further towards her womb, and her asshole grew even tighter. Rimuru could still pull out, but it would be exerting more effort than he expected to escape a butthole. He knew that Shion would loosen up if he came inside her. He was simply waiting for the right moment to fill her up. Shion had given him permission to go rough, and there was a fetish in the doujinshi he had read back on Earth that he could do as a slime. To do it as a human would be near impossible.
He created a liquid within himself that had the same consistency and thickness as semen. It was a modified form of slime, so it lacked any actual sperm, so Shion could be filled with it when she was ovulating - and from how horny she was now, she was definitely ovulating - and she ran no risk of getting pregnant. It would eventually turn watery and leak out of her like a stream of clear pee. Rimuru was so proud of himself for thinking of it that he almost forgot he was still inside Shion.
"Shion! I hope you're ready to be cumflated!" said Rimuru.
"Cumflated? You can't mean..." Shion said.
Rimuru sprayed a heavy blast of slime cum from both of his tentacles, filling Shion's womb and stomach at the same time. Shion saw her belly start to swell, at first looking like a muffin top before becoming round and ball-shaped. It reached the floor, and kept going. Rimuru wondered how far he could go, though he knew the Great Sage would stop him before it became truly dangerous for Shion. He sprayed more, pushing Shion's belly far beyond her breasts. She looked like she was pregnant with multiple babies, big enough that not only would her business suit not fit, all but the loosest clothes wouldn't be able to contain her belly.
Stopping the flow of his slime before he lost too much, Rimuru popped his tentacles out of Shion and hopped off her butt. Shion rolled over onto her back, the full size of her cumbelly becoming apparent. It was stretching far beyond her breasts, taut and swollen to a degree that an ogre could handle, but a human probably couldn't. With her stomach and her womb filled with Rimuru's special slime, Shion rubbed her belly, feeling the gurgling warmth inside it that Rimuru had gifted her with.
"It's so round and tight," Shion said. "It's pressing down, but it feels so good."
"You wear a big belly really well," said Rimuru. "Kinda proud I was able to do that."
"If it didn't interfere with protecting you, I wouldn't mind if my belly looked like this all the time, all bloated and filled with slime," said Shion. "It's so good I'm going to... cum!" Shion squirted onto the floor. Pressing her hands against the floor, she forced herself to stand up. Her breasts wobbled and her belly shook as she righted herself. She was so belated that her belly stuck out of the door to the outside before any other part. Naked and looking gravid, Shion looked out across the city of Rimuru.
"Once we've achieved peace, I really do want to have your babies," she said. "We'll have a large ogre family. I know what you gave me isn't really your semen, but it still feels really good."
"Yeah..." Rimuru said. "But now there's no room for you to rest your boobs on me!" Rimuru didn't think this through. He would have to wait until half an hour later, when Shion finally emerged from the toilet, her pussy and ass drained of his slime and her stomach back to its normal shape.
"Great Rimuru, come here," said Shion. She rested her bosom on his head once again. Rimuru let out a happy sigh. That felt much better.