Anger had been the primary emotion only a few moments ago, and it was taking Dean a few minutes to catch up with his body, which had obviously reacted much differently than he expected. Cas had been gone for far too long, he assumed kicking ass and taking names upstairs, but that knowledge hadn't made it any better that he was gone, or that he wasn't answering when Sam called. Dean could never know what was happening up there, and he couldn't know if his friend was even still alive. The chaos on earth had to mean something big was going down with the angels.
And all of that made sense. It was logical, to worry about your friend when there was supernatural anarchy in heaven.
What did not make sense to Dean, however, was the visceral reaction he was currently having to the angel's return. In his recollection, he wasn't the sort who went about kissing his male friends... And he was pretty sure that was the kind of thing he would recollect doing. Yet here he was, pinning the angel to the side of the Impala, pressing their mouths together as though Castiel was a particularly fine little dish from a bar. But it was different. It was Cas. He was heavier, sharp, solid, and apparently his body was a little ahead of his thought process too. He was kissing back aggressively. Something was keeping Dean from reacting in the way he expected himself to react.
His expectations had nothing to do with warm lips against his, and his fingers going to places that they really shouldn't. His expectations did not include the heat of Cas' body against the back of his hand as he tucked deft fingers into the band of the angel's trousers and pulled their hips closer, he thought however that his other hand might be behaving itself better, and frantically working to rectify whatever the hell was happening. Instead he found his hand on the side of Castiel's face, his thumb resting along the vessel's cheekbone, perhaps a little harder than he should, his fingers curled into Cas' hair and pressed into the back of his neck.
The sound Castiel made reinforced the fact that he was not one of Dean's usual girls.
It was something between a growl and a grunt and the way he shoved into the kiss that Dean had started almost knocked their teeth together, but for some reason this sharp reminder of what exactly they were doing did not bring either of the men to the realization that they were making out like a high school couple against a car from the 60s and could easily have been in a scene from an alternative modern version of Grease.