Really, once Sam had fallen asleep, the night just flew by. He vaguely knew that Castiel got up well before him, but as he didn't hear any signs of pain or major discomfort, he let the kiss lull him back to sleep.

So when he enters the kitchen, blurry-eyed and in need of coffee, he's a bit surprised to see Dean there. The grin surprises him, too, before the question makes its way through his brain. "Huh? Oh, yeah, we're good. Just a bit of a difficult night. Cas was in a weird mood all last night."