A/N: Alright. This was... huh... traumatizing. Warnings: Underage sex (possibly non-con), incest.
At seven years old, Sasuke was a smart child. He knew that his brother wasn't exactly all right in the head. He also knew that kisses shouldn't involve your penis.
Sasuke knew that there was something wrong about Itachi kissing his penis. It felt weird. Penises were dirty, weren't they? Was Itachi trying to clean him like cats do? Maybe Itachi thought he was a kitten. "You're silly, nii-san."
Itachi had chuckled a dark laugh, poked his forehead and told him, "I love you, otouto."
At eight years old, Sasuke was a wise child. He knew that life could be ugly sometimes. He remembered the knife in his brother's hand and the bodies of his parents. Sasuke hadn't understood at first why they wouldn't get up and kiss each other better like they should have.
He'd understood a few moments later that they would never rise again. Itachi had taken his hand, then. Itachi had licked his fingers. Itachi had wanted to be a cat again. He wanted Sasuke to play kitty.
Sasuke was too busy crying his little heart out and trashing around to realize what Itachi wanted. Maybe if he'd played kitten before, Itachi wouldn't have been so mad and mommy and daddy would still be alive. The blame was too much for Sasuke's small shoulders and he cried all the tears he had around his brother's penis, trying to gain forgiveness.
At ten years old, Sasuke was an angry child. He didn't understand why he needed to hit things, sometimes. He just did. Kakashi was his new dad, they said. But Sasuke didn't want a new daddy.
So Sasuke fought Kakashi; bit his hand, pulled his hair and glared with all his might. No matter what Kakashi did, he would never be Sasuke's new daddy. He wouldn't.
One day, Sasuke saw Kakashi outside in the rain. Kakashi looked sad. Sasuke couldn't tell whether he was crying, but he looked so sad. Kakashi wouldn't be Sasuke's new daddy, but he shouldn't cry. Tears are evil.
So Sasuke went outside in the rain and with his small hand, grabbed Kakashi's sleeve. The man followed the little boy inside their house. Still Kakashi wouldn't talk. He'd just look at Sasuke and the boy felt hurt, like he'd fallen hard on his chest and it bruised.
Sasuke felt tears come to his eyes and he knew that Kakashi looked so sad because of him. Because he'd been so mean and he was a bad child.
Shivering with the realization, Sasuke approached Kakashi and his small, agile hands managed to unbutton the pants, then lower the zipper to release Kakashi's penis.
Sasuke would make it better. He wouldn't wait this time. Cat-like, Sasuke licked the tip of Kakashi's penis. It moved in his hand, but before he could kiss it properly, Sasuke felt two large hands on his shoulders holding him back.
Looking up at Kakashi, puzzled, Sasuke saw real tears on the man's face. The boy flinched and looked down, "I'm sorry." He didn't know what he was apologizing for, but it seemed like the thing to do.
Before long, Sasuke felt himself pulled up close to Kakashi in a tight hug. It hurt his chest even more. "It hurts." Because it was the only thing Sasuke knew how to say.