Hiii... so uh, 

Abt that question I asked yesterday, everyone responded that they would like me to try smut, so here it goes!

Apology for the angst in yesterday's chapter ig 😋

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It was tranquil in Muzan's office as it was nearing sunrise. Muzan was experimenting, working on some sort of new concoction. Kokushibo lay peacefully on his shoulder, waiting for him to be done. Since it was Friday morning, Kokushibo knew that they were about to have sex. It was their routine, and Kokushibo wanted to stick to it exactly.

While both Muzan and Kokushibo were fond of sameness, Kokushibo was the one who instated this routine. Every week on Friday morning, they would share more intimate quality time. It comforted him to have this routine, and it helped him plan his training much better, as after they did such activities together, Kokushibo did not like to train.

But he was getting a little antsy. Muzan was doing his work longer than usual, and it was nearly time. He didn't know much about Muzan's work, but he knew that he wouldn't finish in time and would mess up their routine. He knew that he should be a little more flexible, but this was their time and he didn't want some sciency stuff, no matter how important, to change that.

"Koku darling~" Muzan said, breaking the silence as he put his thumb and pointer finger around Koushibo's chin, making him look at him. Muzan sighed. "Don't get upset, but I still have a little bit of work to do." Kokushibo huffed, making a little 'ugh' noise. "I know, I know, but-"

"Muzan... this is supposed to be our time.. not work time..."

"Let me finish, my love! I think you'll like what I'm proposing." He chuckled. "I don't have much work left to do, and it's pretty simple. So, why don't you sit under the table and use that cute little mouth of yours while I finish up?"

"My mouth...?" He thought for a second, then realized. "Ohh... that, ...yes.." He blushed slightly.

"Is that okay with you?"

"Yes, ..but, uh... do you think that.. I'll fit..?" Muzan moved his head so he could look under the desk.

"I'm sure you will! But if you want me to, I'll scoot the chair back a little."

"It's okay, ..I'm sure you're right..." Kokushibo unfurled his legs, scooted to the edge of the seat, grabbed on the edge of the desk, ducking under and lowering himself down so that he was sitting like he usually does. He put a hand on Muzan's knee, and watched as he gracefully undid his belt and handed him his member. Kokushibo gently put his fingertips on the underside, and leaned in.

He blushed as his mouth enveloped Muzan's  cock. He was used to it, so he wasn't really embarrassed, per say.. he couldn't put a finger on what he was feeling. It didn't matter now, though. Kokushibo leaned his head to the side so that he was leaning against Muzan's inner thigh.

"Y'know dear, just because I'm doing a little work doesn't mean that you can't actually suck." Muzan told him, noticing that Kokushibo was just resting with his dick in his mouth. 'Oh..' Kokushibo thought to him, then started to obediently suck. Muzan put a hand on his head and gently stroked his hair, glancing down lovingly before returning to whatever he was working on. "Mmm,..~ Koku, you're doing sooo good, as always~" He said after a few minutes, trying to keep his focus and composure. 

'Thank you...' Kokushibo thought, 'purring' a little as Muzan complemented him and gave him a little head pat. His blush intensified as he heard Muzan's voice. He was (not so) secretly proud that he could make Muzan like that, or sometimes even a complete mess. He knew it meant that Muzan was pleased with him,  which in turn made him fill with joy. All Kokushibo wanted to do was make Muzan happy, and he liked it when he could directly see/hear it.

"I'm done.. with working, Koku.." Muzan said after a few more minutes. "But don't stop, 'kay~?" Kokushibo nodded, he now had Muzan's full attention. He placed a hand on the back of his head and pulled Kokushibo deeper onto his member. He rolled his hips, thrusting into Kokushibo's mouth, squinting one of his eyes. Kokushibo maintained his total concentration breathing as Muzan continued, his hand now tightly gripping his hair.

Kokushibo wrapped his arms around one of Muzan's lower legs, bringing it close to him as if it were a plushy. He felt good from seeing how Muzan felt good, and from what Muzan was doing. He liked the texture of Muzan's skin against his, and the taste of it as well.

"Koku darling,~.. can I finish... in your mouth~..?" He asked, to which Kokushibo nodded. Muzan rolled his hips once more, releasing precum into his husband's mouth, who swallowed it. Kokushibo pulled off Muzan's cock, then pulled himself back into the chair that he was previously sitting on, leaning up against his husband's shoulder once again.

"Did I ever tell you... that you taste like.. vanilla?" Kokushibo said, holding one of Muzan's hands.

"Mmm, you haven't..!" Muzan replied, relaxing. "Sorry to keep you waiting, my dear. I assume that you want to do the rest in the actual bed, correct~?"

"Yes..."

"Splendid!" Muzan picked up Kokushibo, gently throwing him over is shoulder, placing a hand on his lower thighs and his lower back. Their room was connected to the office, so there was no need for teleportation or redressing. Muzan opened the room door and entered, locking it behind them. He then sat them both down on their bed, pulling Kokushibo into a kiss while gripping one of his thighs.

Muzan licked Kokushibo's lips, then entered after they parted. Muzan started to loosen both of their outfits. He started with Kokushibo's, pulling at his belt so that his top would loosen. He pulled the yukata off of Kokushibo's shoulders, exposing the upper part of his chest. Muzan broke the kiss, pulling back to admire Kokushibo.

"Looking good, moontits~" He chuckled, putting a hand on Kokushibo's chest.

"Did you just... actually.. call me... 'moontits'...?"

"Yeah-huh!" He chuckled again.

"Yeah well... uh, ... I don't have.. a dumb, annoying nickname... for you right now.., but! ..I'll think.. of one...!" Kokushibo removed his hands from the sleeves of his yukata, letting it fall off him, only connected to his body because his pants were wrapped around on top of it. He reached his arms up to pull on the collars of Muzan's shirt and vest.

"You do that." He teased. "And while you're at it, finish taking off your outfit for me~"

"Okay..~..." He replied, removing his hands from Muzan's collars to his own outfit. Muzan did the same, pulling his hand off of Kokushibo's thigh to do all his buttons. Kokushibo took a little longer than Muzan, despite having most of his outfit loosened already, because he made sure to delicately fold  his clothes and place them on the nightstand, as well as taking out his hair.

"So cute~!" Muzan said, bringing Kokushibo into a close hug, pressing their bodies together. He laid them both down, him on top of Kokushibo, and positioned his head to be in the crook of his neck, and bit down, earning himself a small gasp from his husband. Muzan then put a few of his fingers to Kokushibo's lips, pulling away from the bite to order: "Suck."

Kokushibo obliged, opening his mouth to Muzan's fingers while Muzan marked up his neck, shoulders, and upper chest. After 2 or so minutes, Muzan pulled his fingers out of Kokushibo's mouth, and swiftly moving them to his lower hole, pushing one inside. 

"A- ..~.... H-hey..." Kokushibo winced a little bit. 

"Sorry dear, I forgot to warn you." Muzan licked Kokushibo's neck and sat up, gazing down at his husband.  

"It's.. fine.. ~..." Kokushibo said, quietly moaning as Muzan slipped a second finger in, gently thrusting them. Luckily, Muzan had retracted his claws. He then put a hand on Kokushibo's waist, gently caressing him as he continued fingering.

"I like the little sounds you make, darling~! They're SOOO cute! I have to listen closely to hear them, though, which is even cuter! They're just for me~" Muzan leaned down to kiss Kokushibo on the cheek, pulling out his hand and placing it on his shoulder. "I'm gonna flip you over now!" Muzan warned, then a split second later Kokushibo was laying on his stomach. Muzan leaned down next to one of Kokushibo's ears as he lined himself up, loosely gripping a chuck of his hair. "Are you ready~?" He asked quietly, to which he got a nod in response.

"Ha..! mm..~..." Kokushibo quietly yelped as Muzan pushed himself in with a singular thrust.

"Do you like that sweetheart~?"

"Mmhmm, .. yea..." Kokushibo responded, to which Muzan tightened his grip on his hair as he sat all the way up. He wrapped the chunk that he was holding around his hand as he set a fast pace. He held one of Kokushibo's hands, squeezing it tight, yet lovingly as he continued to thrust into his six-eyed partner. Kokushibo whimpered slightly, but was feeling good.

"Oh, Koku~! I find it soo cute when you start sweating here, but never in training or battle, which is an arguably more intense activity, given how hard you work!" He chuckled. "It makes me feel so special."

"You.. a-..are.. special... mm.." He panted. He was working on maintaining his moon breathing, so his speech pattern was even slower and more broken up than before. 

"Awwh, thanks sweetie!" Muzan leaned down to give Kokushibo another bite, this time on the back of his neck. He kept going, increasing his speed and caressing Kokushibo's cheek. Muzan swore that Kokushibo just kept getting cuter every second. Seeing him, like this or in general, just made him so happy. He was glad that he could make Kokushibo happy in the same ways.

"Mm.. Muzan...~..."

"Yes moonlight?"

"Mmm.."

"Did you wanna say something, or did you just wanna say my name?" Kokushibo held up two fingers, signaling the second one. "Awwhhh!! Cute. Now tell me darling, do you feel close?"

"mm.." Kokushibo thought for a moment, then nodded and said "Mmhmm...~..."

"Great, 'cause me too~!" Muzan kissed Kokushibo on his cheek again, then increased his speed and strength once more. Kokushibo reacted by closing his eyes and tensing up a bit, but he adapted relatively quickly.

"Mess... no.. want..."

"You don't wanna make a mess, why? We'll wash and change out the sheets like we always do."

"Blanket.. favorite... soft..."

"Ohh, I see! Can I pull it out from under us then, so it doesn't get dirty?"

"Yeah..." Muzan removed the blanket from under him and his husband, and tossed it onto the edge of the bed so it would stay clean and they could use it when they went to sleep later.

"Shall we cum together, darling?"

"Where... are we going...?" Kokushibo asked hazily.

"Cum as in C-U-M."

"..I see.. uh, ...yes..~.. mm" Muzan increased his speed for the final time, then after a few minutes they both finished: Muzan inside Kokushibo, and Kokushibo on the sheet. Kokushibo lifted himself up a little in an attempt to stay clean. After making sure every last drop of his resided inside his husband, Muzan pulled out and flipped his husband over again, laying down next to him.

"Do you want to clean up now and sleep later, or clean up later and sleep now?"

"Clean now.. please..."

"Alright-y!" Muzan picked Kokushibo up and brought him to the extravagant bathroom that connected to their room. Muzan ran the water for the big tub, sitting Kokushibo down and wrapping him in a towel. "I'll be right back, okay? I'm just gonna make the bed."

"Okay.." Muzan pat Kokushibo's head then went to go change their sheets. When he came back, the water is mostly filled, so they stepped in. Muzan washed and brushed Kokushibo's hair, then put it into a braid so it wouldn't tangle while they slept. After they were clean, they laid in the warm water for about an hour, talking about things. Kokushibo was still a bit hazy, but his speech was back to normal and he was fully regenerated. 

When they stepped out of the tub, Muzan wrapped himself and Kokushibo in their expensive towels, and dried the two of them off. Once they were dry, they got into comfortable clothes to sleep in, and got back in bed. Kokushibo nuzzled up to Muzan, wrapping his arms around him and giving him a little kiss on the cheek.

"Awwh!" Muzan returned the kiss, then gave him a soft peck on the lips. He wrapped his arms around him, stroking the back of his head/hair.

"I love you, Muzan.."

"I love you too Koku!! I hope you had fun!"

"I did... that's why.. it's on the routine..." He said as-a-matter-of-factly. "Then tomorrow.. we go out for a picnic dinner... then cuddle.. then on Sunday.. we spend the whole day.. cuddling.. and being together..."

"I can't wait" And that was the last thing said before the pair of silly grandpas drifted off to sleep.

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2214 words 

How was that 😀

Imo I don't think it was THAT bad, but I think I could work on the pacing a little..

Will I write smut again...?  Idk. If ppl like it and/or request it again maybe I will.