Thankfully being a virgin doesn't make Cas completely stupid, so when Dean pulls the hem of his shirt up Cas takes the hint and yanks it the rest of the way off, hurriedly tossing it aside. He takes advantage of Dean's hands elsewhere and ducks his head to scrape his teeth along Dean's jaw, the stubble like sandpaper.

Cas's hands roam all over Dean's torso, one pausing to trace the handprint on his shoulder as the other strokes across his chest, fingers catching on his nipple. Cas isn't really doing anything specific; he's just touching Dean as much as possible, doing as much as he can. There's very little thinking going on, since most of his blood is rushing straight down to his dick.