Dean jerked back from the kiss, his head thumping against the floor, and he tugged at the arm that was pinned, his other hand digging fingertips into Sam's shoulder. He wasn't sure what to do. He couldn't deny he had always felt far too much for his brother, feelings he didn't understand, but Sam wasn't in any state to do this, he couldn't have been thinking straight.
"Sam... you don't mean this. You only just ended things with Amelia," he murmured, but his free hand had slid into Sam's hair and he looked up at his little brother. He knew, on instinct, that Sam was no doubt a rough kind of person when it came to love and sex, but he was trying so hard not to think about that.
It didn't even occur to him that this was a guy. It was just Sam. And Dean leaned up a little, his mouth hovering near Sam's. "We're brothers, and you're not in the right mind right now." If he came up with excuses, maybe it'd be easier to brush aside. Slim chance of that.