For Tomorrow's Sake | Various!JJK x Reader

At scarcely thirteen years of age, you've become an aunt.

It sounds a bit ridiculous, and even though you're not technically related to Toji, you're his little sister in spirit. Now, your big brother has a child. Which makes you an aunt. No matter how much anyone tries to convince you otherwise.

"You're too young to be an aunt," Satoru frowns. "We're just teenagers."

"So? There's no rule that says teenagers can't be aunts or uncles. It's all about perspective, Satoru."

You're rocking Megumi in your arms as he looks up at you with big, beautiful eyes. You pause for a moment, then plant a kiss to his pudgy cheek. Megumi continues staring at you with a mixture of confusion and awe. You kiss him again, and this time, he giggles.

Satoru really hates that he's getting jealous of a literal baby right now.

"He has a weird face," Satoru rudely declares.

"No, he doesn't," you frown. "He has a cute face."

"It looks more weird than cute to me. Also, he's stinky all the time. What's wrong with you, huh? Stinker."

Satoru proceeds to lightly jab his finger against Megumi's forehead, accentuating his words with a firm motion. Megumi blinks several times, no doubt trying to process what just happened. He doesn't really react much, though. In fact, after staring at Satoru for a few seconds, he disinterestedly turns away, much more in favor of looking at you.

Needless to say, Satoru's ego doesn't handle it well.

"Did you see that?" he exclaims. "The little stinker just scoffed at me!"

"Babies can't scoff, Satoru." You roll your eyes at him. "And stop calling him that. He's not stinky. He smells nice. Newborn babies always have a nice smell. It's comforting and makes you want to keep holding them forever and ever."

"He smells nice right now," Satoru counters. "I bet in about ten minutes he's gonna poop himself again. And whenever he does that, it really, really stinks. It's even more disgusting than your cooking, which I didn't think was possible."

"All babies poop themselves. It's not like you were an exception," you sigh.

The same applies for you too, of course, although your case is slightly different. After all, you weren't really a baby when you awakened in this world. You had the knowledge and mental awareness of a teenager. Which made it all the more humiliating whenever people had to change your diapers. But for the sake of your sanity, you're doing your best not to think about it anymore.

"Be nice to baby Megumi," you say, proudly holding him up in the air, like Simba. "Look at him. Isn't he such a sweetheart? Since I'm the cool aunt, I'll let you be the cool uncle, okay? And everyone likes the cool aunt and uncle."

Satoru blinks. "You're the aunt, and I'm the uncle? But that makes it sound like..."

...like we're married.

He doesn't say that last part out loud, but the realization makes his cheeks redden. It also makes him grin smugly, when he thinks of how furious stupid Naoya would be. Which is definitely an added bonus.

"Fine," Satoru relents. He pokes Megumi on the forehead again, but this time, he's smiling. "I guess it's not his fault that he's stinky sometimes. And he barely ever cries, which is nice. He's a pretty good baby, all things considered. Also, I am really cool, so it makes sense I'd be the cool uncle."

"Of course," you grin. "You're super cool, Satoru. He's definitely going to love you. Ah, but not as much as he's going to love me. Don't feel discouraged when I end up being his favorite, okay?"