Dean grabbed Sam's face and kissed him gently. "Don't stress yourself out over this, Sammy, please. You've moved on. It was a time in your past that you don't like thinking about, and you're moving on."
"I don't want you to ever be ashamed of ANYTHING in your past, Sammy. Sure, it was something you probably shouldn't have done, but it's done. It's in the past. You and me now, okay? I'll take care of Lucifer."