Requested by Anon on tumblr.
Hypocrisy
The initial shock of finding out that Dean and Cas were in some kind of relationship took a while to pass. Sam claimed that it probably had something to do with walking in on them having sex, while Dean brushes it off as Sam being a pansy ass little girl. When Sam was finally able to look at Dean without having flashbacks to that moment, he confronted him on the issue.
"I don't see what the big deal is, Sammy," Dean said, biting into a hamburger.
Sam was flustered. "Well… Maybe I just don't like the idea of you boning and angel."
Dean stopped chewing for a moment. He set his burger down on the plate and swallowed.
"Don't you think that's a bit hypocritical?" he said, narrowing his eyes. "Tell me, how is Gabriel?"
Sam's mouth flew open. Then he pursed his lips. "I don't know what you're talking about."
"You are such a bad liar," Dean said.
"Fine. But come on, this is Cas. After everything he's done…"
"You're right. I mean, killing people to get his rocks off, trapping us in a time loop so he could kill me over and over again, trapping us in TV land. I shouldn't be sleeping with someone – Oh wait, that's your boyfriend."
Sam had no response to that.
"See, you know I'm right," Dean said, returning to his burger.
"Wait," Sam said a few moment later, a small smile starting to form. "Did you just imply that Cas is your boyfriend."
Dean almost choked. "I said no such thing."
"You totally did!" Sam grinned. "You know what, I like you and Cas together. I think he's a good influence on you. I'm just worried you'll be a bad influence on him. I like Cas. Don't screw this up."
Dean took a swig from his beer. "You done with your little chick-flick moment?"