Sam, afraid of Dean after the first time he saw Dean kill a regular human -- No possession, no nothing, and yet he still put a bullet in the old bastard's head.
He stood there, frightened beyond reason, hands shaking. He was still a kid, voice still high and sweet.
Dean's eyes were dark, fixated on his victim. A spark had lit within his soul, a black spark, eating at every bit of light his youth had left him with.
"Dean...?" Sam asks quietly, so quietly Dean almost doesn't hear him.
Dean's head is quick to snap towards Sam's soft voice.
"Sam." Dean affirms.
"What- uhm, what just happened?" Sam's playing with his own fingers, twiddling them and cracking joints and Dean takes notice, a slight rush running through him. He knows he scared Sam.
"Nothing." And Dean is suddenly mere inches away from Sam, breath shaking the kid's eyelashes. Sam keeps his gaze down, looking at the dirt.
"Nothing.. nothing," Dean keeps repeating it, surely only trying to convince himself now.
And then his lips are on Sam's. He could never tell you why, Hell he doesn't know for himself. But he kissed his baby brother, right then and there.