Okay but I have this other headcanon that Dean’s eyes go black whenever he gets turned on.
So Cas does his growly voice and - black eyes. Or Cas lifts something heavy and - black eyes. Or Cas gets pissed and beats the crap out of Dean again and - black eyes.
And Sam is the one who catches on.
A moment of silence for Sam continuing to endure years of ridiculous interspecies sexual tension.
sorry but it suddenly made me remember this (x)