Jujitsu Kaisen x SukunaSibling!Child!reader

Sukuna Siblings Day Out

Today, it was time for some sibling bonding.
Sukuna summoned Yuji to his inner domain to explain what he wanted.
"Oi brat. C'mere," He gestured, "I want to hang out with my sibling today, think you can switch with me?"
"And what's in it for me? I'm not a fool anymore, and I have a name!" Yuji countered. Sukuna rolled his eyes.
"Yea yea, I know, brat. I haven't seen my sibling in over a thousand years, think you can go without seeing megumi or nobara for a thousand years?" He sneered. Yuji paused to think. Could he really go so long without seeing his friends?
"I'd have to ask Gojo sensei first, and there's a bunch of things to do to prepare, but overall, I think you could." Yuji thought out loud with his hand on his chin.
"Good." Sukuna said before expelling Yuji from his domain. Yuji didn't have time to react before he was back in his room. He calls Gojo to let him know what happened, along with what Sukuna wanted. Gojo nodded as he listened to Yuji, already writing down and showing Principal Yagi.
As long as Sukuna didn't do anything other than promised, he was allowed.

6:00 am
Morning

Yuuji woke up to a weight on his stomach. You were jumping up and down in excitement and wanted to start early. Yuuji got up and got his body ready for Sukuna to take over and send a message to Gojo to let him know he was up. Gojo replied with a thumbs up. After getting ready, it was around 7:30 am.
Gojo had arrived and was waiting for Yuuji to switch with Sukuna.
Sukuna woke up on his throne to Yuuji, calling his name. The curse king grinned and took over with ease.

"Onii-chan!" You cheered as you saw the marks appear. Sukuna grinned as he saw you smile.
"Hello, my blossom. I missed you so." He said, giving you a face rub before planting kisses all over your head. You giggle and try to tell him to stop, but no avail. He continues to make you giggle before your stomach interrupts your reunion.
"Is my blossom hungry? I don't sense any curses anymore, so human food will have to do. How does some traditional rice with miso soup, some fish and vegetables sound? I'm a bit rusty, so believe in me." He joked. You nodded vigorously to taste your brother's cooking.
Gojo sat silently, watching the interaction. Sukuna was only emitting cursed energy when looking for curses to eat. He must be truly happy with you around.
You watch in wonder at your brother cook. His fish was always to die for. Soon, the dining area was filled with aroma even Gojo succumbed to. The clattering of plates and chopsticks fill the air as the siblings ate, well, you ate. Sukuna didn't need to eat, but ate the bites you offered using different mouths to get a squeal of excitement from you. It was only close to 9 when you finished, and next was getting you ready for a day out. Sukuna took your dishes to the sink, placing you on his shoulders. He then headed to the bathroom to clean you. A bath was prepared, and Sukuna undressed and bathed you.
Squealing and laughter from both you and Sukuna were heard outside the bathroom. Gojo was relaying what was happening to the principal. Soon, you came out dressed in a kimono similar to the one your brother wears in Yuji's mind. You were a spitting image of Sukuna, if not for the size and hair. The marks hadn't appeared yet, so Sukuna asked.
"Blossom, where are your marks?" The marks faded onto your skin like it does on Yuji. Now you were a mini Sukuna. Gojo took a picture sneakily and sent it to yagi.
"Alright, blossom, it's time to go! Are you ready?" Sukuna asked. You nodded happily, holding onto your brother's shoulder and hair.
You both leave the dorms into the world. The sun was hitting your face and illuminated the way to the park. The playground was empty at this time, so you didn't have to share it with anyone. You head for the swings to compete who can swing higher between you and your brother. Sukuna stiffened slightly, turning to see Gojo looking away with a strained smile. He tried to reason with you and agreed to push you. You giggle and say 'ok'.
After about 2 hours of going through the entire playground, it was time to go to your next location.
Dango.
Something in common for both human counterparts of the Sukuna siblings.
They both loooove dango. So when there's stars in their eyes, you know it's serious.
Unfortunately, Sukuna can't just take it in today's day and age, so Gojo handed them money to spend. Sukuna was cringing when he handed the lady money.
Why couldn't he just take it like the king he is?
After getting the dango, the two sat down on a bench, Gojo chilling under a tree. You took a bite of the dango and accidentally let a chunk fall. You reach down to catch it, but your brother caught it with the hand he was holding you with. The dango you were holding was also pointed at his mouth, so he took a small bite. You noticed and whined at your brother. He just laughed with his mouth full.
After eating the dango, you wanted to take a nap. Sukuna brought a blanket miraculously and settled somewhere shady. Laying the blanket down, he slowly sat down with you in his lap. Your breaths started to slow and even out as Sukuna ran his fingers through your hair.
"My sweet blossom, one day, we'll be the most powerful curse and demon rulers of this world." He whispered as you fell asleep. Once you were asleep, Gojo came up to ask.
"You must be really happy right now, considering I feel no cursed energy leaving from you." Sukuna rolled his eyes. He's soft because you're the only one who understood what the world did to him when he wanted to live forever, so he could've made the world a better place for someone like you.
"What do you want, 6 eyes?" Sukuna turned his head to look at the white-haired male, obviously irritated to be interrupted.
"Just checking in. Did you forget you're 2 people in one?" The cheeky male retorted. Sukuna scoffed.
"Yes, and I'm in control, no humanly behaviors. Are you going to leave soon? I want to rest." As Sukuna said that, a feeling pooled in his lower abdomen.
"What is that feeling right now in my lower abdomen? It's quite uncomfortable." Gojo giggled.
"Looks like Yuji needs to pee. I'll watch them while you go. There's a park bathroom over there." He points to a building in the middle of the park. Sukuna carefully places you down, laying on your side. He (basically) teleports to the building and does his business. Gojo then realizes he probably doesn't know how to use a modern toilet, so he goes to help, leaving you alone.