Itachi has known for a long, long time that he had Sasuke wrapped around his little finger. He's known ever since they were children, when Sasuke would watch him train, bright-eyed and bushy-tailed, clapping when his older brother hit every single target with ease, and when he dashed to pick up the kunai as soon as Itachi had expertly landed from his intricate back flip-spin. He would watch Sasuke as Sasuke would watch him: he remembered how he would follow him around like a puppy; even before his heart went cold, Itachi had worked to keep his brother amazed, in awe of his every move. The older Uchiha had wanted Sasuke to place him high above the rest of the clan, above the rest of the world, so that when he knew the time was right, the person he chose would be the one to kill him.
In order to strengthen the bonds of admiration and brotherhood that Sasuke felt for his brother, Itachi would constantly test the youngest Uchiha: whenever the boy wanted to train with him, he would show little spurts of rare fondness, always promising later, Sasuke, with an endearing flick to the forehead and a small smile half-faked over his handsome face. Itachi was always sure to ensnare Sasuke's affection by inviting him along to watch his practices, although always making sure that Sasuke felt inferior by the end so as to ensure the highest regard that the younger felt for him.
As time passed, and as Sasuke's education came into play, Itachi began to make the tests harder: not only was Sasuke's emotional reverence needed, but the boy's physical ability to do anything Itachi asked of him.
So it began…
"Sasuke, I want you to catch me a rabbit by the end of the day." Uchiha Itachi called to his younger brother over his shoulder, packing away four of the five kunai he had utilized during the training session. Sasuke was attempting in vain to remove the fifth from a target attached to a tree that was only just out of his reach. At the sound of his brother's demand, he stopped his attempts and focused on his brother, who was sitting with his back against a tree not a few feet away. The 9-year-old Uchiha couldn't help but start when he found himself gazing upon a shirtless vision of his brother: his well-muscled arm draped over his bent knee; his head leaned back against the tree…Sasuke's eyes followed a miniscule bead of sweat trickle down his brother's long, perfect throat, sliding down his toned chest and abdomen…finally resting at the snap on his pants, along the invisible slope where his flat stomach molded into sharp, delicate hipbones.
"Sasuke."
The boy's head jerked up, his own black eyes meeting the shining red of the Sharingan. Itachi hadn't deactivated them yet, and was now staring his brother down. Sasuke was terrified of those eyes when they looked at him, and him alone. Itachi's tone was calm, however, when the silence was broken by his smooth, deep voice.
"Sasuke," he said, eyes still holding onto the younger's gaze like a grapple and chain. "Why are you blushing?"