"No." Dean had been very excited at the prospect of a blowjob, and Castiel wants to follow through. If Dean can't give him instruction then he'll have to start with what little he knows and just be extremely patient.

No teeth, but tongue's good. All right. He can start there.

Cas braces himself with a hand on Dean's hip, leaning back down and swiping his tongue across the head of Dean's cock.