HOLY SHIT
First, WHAT SHE SAID. Especially that bit about Greek myth, which, yes. Let me just say: the Siren's clue for Dean?
HYACINTHS. Seriously. This show knows EXACTLY what it's doing, and is giving us as much Wincest as network TV will allow. SERIOUSLY. Everything in this episode was REEKING with erotic symbolism.
Also: Siren THROAT-EJACULATING into Sam's mouth, so we get Sam with white goo at the corner of his mouth while Dean is pressed up close behind him. SHOW, JESUS. Where can they go from here, but an actual Wincestuous makeout session?