It is quick.
So quick that Dean doesn't realise it happened until a good two seconds after it happens. After Castiel breaks away, lips trembling, eyes frantic, searching for a reaction. It's so quick that Dean doesn't process the fact that- holy shit-
Castiel just kissed him.
There is a lull, one electrified with emotions Dean didn't even know he could feel. The pause seems to last forever; the silence between them static.
"I'm just going to leave, then." Castiel says, and the way his face forms to show his pain could only be described as heartbreaking. Dean is still too shocked to do anything, so he stands, doe eyed and dumb at the memory.
So Cas leaves, out the motel door, without another word.
It isn't until late that night, when Cas enters with a pack of beer, flushed cheeks, and the apology hanging off of his tongue that Dean takes the initiative to walk right up to him and intertwine their fingers.
Cas frowns. Dean guides Castiel's hand to set the beer down on the dresser, never breaking eye contact. The green never leaves the blue. He takes both of his hands in his own, and he begins to tell Castiel something but he can't find the words. They are stuck in his throat.
So instead, he leans in quick before he changes his mind, and the angel's lips are like sandpaper. Rugged, but sweet, after a moment, they move against his in time with his heart, that beats against the walls of his chest as if it needs to break free.
"I think I'm in love with you." Castiel says against his lips, so that Dean can feel the words on his mouth, the words that carry a weight with them like no other.
"I know," He says, the ends of his lips quirking up in a smile.