Tanjiro:
You were sewing with him. Apparently Inosuke had ripped his pants again, and since you knew how to mend clothes, you and him were doing it.
Tanjiro was helping you with the patch on the leg when the needle accidentally jabbed him. "Oh-!"
"Sorry!" You apologized, taking it out. "Are you okay?"
"I'll be fine, don't worry." He just smiled at you. "Keep going, we're almost done."
Nezuko:
Nezuko had gotten into a really bad fight. Originally, it had just been you and Tanjiro, but things got desperate enough that she kicked her way out of the box and leapt into the fray. For a while, you'd lost sight of her... until you saw flames, and realized that she must've been using her ability.
When the fight was over (and the demon was burning to ashes), Nezuko landed in front of you, injured and bleeding, but alive.
"NEZUKO!" You shouted, rushing over to her and tackling her in a hug. The girl grunted when her back hit the ground, and you barely got out a "Sorry" before the tears started flowing.
Nezuko patted your back with worried noises when you began bawling on her, looking to Tanjiro for help.
Zenitsu:
Zenitsu was modeling a spare pair of uniform pants for you. Apparently, they'd gotten the size just a bit wonky, and they were too long on him. Instead of letting them get all frayed and worn at the bottom hem, you offered to sew them for him.
Currently, you had to try and pin them so that you could sew them. You were pretty careful with the pins, but you accidentally stuck him with one and he yelped.
"Sorry, sorry!" You hurriedly apologized, taking the pin out. "I think I've got it now, actually -- so you can take them off."
Inosuke:
Inosuke was being more ornery than usual, and you'd had a shorter temper than you usually had. When he came rushing at you, you'd had about enough.
"STOP!" You shouted, smacking him away with the hilt of your katana. You'd slapped him away before, but you weren't thinking and you had it in your hand. Apparently it hurt more than you'd first thought it would, because when Inosuke stumbled away, he was clutching his head in obvious pain.
You groaned, shaking your head and sheathing your katana. "Shit, I'm sorry. I shouldn't have done that. Do you need ice?"
He just looked at you in surprise. "You hit harder than you look, (mispronounced name)."
Giyuu:
Tonight saw you and your boyfriend having dinner together. You were heating up some tea and he was setting the table for both of you.
He accidentally bumped you while you were pouring tea, causing some of it to splash onto his hand. He pulled his hand away with a startled noise, and you gasped.
"I'm so sorry!" You exclaimed, setting the teapot and cup aside and grabbing his hand. You dragged him to a basin of water. You made him keep his hand there while you finished pouring the tea and got out some healing salve.
You wrapped up his hand (and kissed it, which made him blush) before letting him have dinner. You were extra cautious when he drank his tea that night.
Kyojuro:
You were sparring with him, as you did, when you kicked him a little harder in the stomach than you'd thought you would.
He went down like a sack of potatoes, grunting when the air was forced from his lungs. He clutched the area and grinned weakly at you. "You're getting better at this!"
You were so worried about him that he called off the spar and let you help him back to the porch, where you had him keep a cool cloth against his stomach. He just shook his head with a smile at your attempts to apologize, patting your head and saying it was okay.
Muichiro:
You accidentally sprayed perfume in his face.
You were getting ready for dinner and he'd walked into the room so silently that you hadn't heard him. When you sprayed perfume, the nozzle was pointed at an angle and got into his eyes.
He let out a noise and stepped away, rubbing his eyes.
"Oh! Sorry," you apologized, setting the bottle down. "Are you okay?"
"I'm fine," he replied, blinking his watery eyes. "I'll be right back."
He walked out of the room, intent on washing out the sweet-smelling liquid. He didn't come back for at least fifteen minutes, and when he did, the ends of his hair were wet (he'd stuck his face in the pond).
Shinobu:
You were doing Shinobu's makeup. You had her face powdered and her lips done, and now you were carefully rimming her eye with liner.
Something happened to startle you, and the flinch you did accidentally made you stab her in the corner of the eye with the liner pencil. She sucked in a harsh breath through her teeth, clapping a hand over her eye.
"Oh my gosh, are you okay?" You worried, setting the pencil down to check her eye out. When she opened it, it was watery, though you didn't see anything other than some redness.
She tried to smile. "I'll be fine."
Gyomei:
You accidentally scratched him with your nails. You were overdue to clip them, and when you were scratching his back you dug a bit too hard, drawing blood.
He didn't say anything at first, so you hadn't really noticed until you saw the red welling up along the path.
You panicked, grabbing a piece of cloth to dab at the injuries. You apologized, and he forgave you pretty quickly, understanding that it was an accident.
Sanemi:
The two of you were in an intense game of tug-of-war over the towel. You were giggling, he was growling playfully, and all it took was one hard yank from you to send him sprawling across the floor, hitting his cheek on the floor.
He groaned, lying there for a second before peeling himself off the floor, giving you a look. "You're paying for that."
You squealed when he jumped up, hauling you over his shoulder as he marched towards the hot spring.
Akaza:
You were trying out some poison on your blade. Akaza had taken the katana to inspect its sharpness and, before you could let him know, he accidentally sliced into his finger.
He snatched his hand away with a soft curse of pain, glaring at the katana. When you softly said "Sorry", his expression melted, and he shook his head at you.
"It's fine," he said, and when you brought him a cup of blood to try and make him feel better, you promised not to tip your blade with poison without letting him know first.
Douma:
He was being a bit too voracious with his appetite, so you fought him off. You were still weak from illness, so you couldn't exactly shove him off, but you gripped his face with both hands and yanked.
Your nails dug into his skin and cut him deep enough to leave deep scores along his cheekbones. When he realized that you were trying to get his attention, he stopped biting into your shoulder and gazed at you in surprise.
"Please be more gentle," you hissed with a wince.
"Right, sorry, Dove," he cooed, his heart doing flips. He'd admit to you later that you hurting him like that was a deep turn-on.
Kokushibo:
You were cultivating a fire, humming to yourself. You were on a small trip with Kokushibo to your aunt's home, and at the halfway point you decided to set up camp near the river.
Kokushibo had gone to secure the area forever ago, and he was so quiet that you had no idea he'd come back. He stood behind you, watching you work.
When you got up, his arms around you made you momentarily freak, and you grabbed the stick you were using to tend to the fire and you thrust it at his neck.
It barely went in, of course, and chipped off as soon as it made a cut, but you realized it was your lover and let out a shaky breath. "I'm-- so sorry, Kokushibo, are you okay?"
"It barely drew blood," he replied, taking the stick from your hand. True to form, he'd already healed so that you could never tell you'd actually gotten a hit on him.
Muzan:
You pricked his hand with a small blade you were using to cut apples.
His lips curled down for a moment, but his healing factor kicked in almost immediately and it was like there was never anything there.
"Sorry," you said sheepishly with a laugh. "I'm not that good at cutting apples."
He shook his head in amusement, taking the half-peeled apple from you. "Here, let me do it."
Yoriichi:
You and Yoriichi were walking together. You were telling him a story about your oldest sibling, gesticulating with your hands. He listened with rapt attention, and during one of the best parts, you thrust out your arm and accidentally caught him across the abdomen.
You paused, looking at him in shock. "I'm sorry! Are you okay?"
He nodded, making a gesture for you to keep going. You had hit hard enough for it to be uncomfortable, but he was going to ignore it by listening to you talk.