Dean doesn’t really like cock, but she likes Castiel - enough that his disinterest in gender counts for something, enough that when she tries fingering herself to the thought of fucking him, she comes - but not necessarily to a heteronormative thought.
Several weeks into their relationship, after many entertaining sessions of making each other come through sucking, licking and groping, Dean pulls out one of her dildos only for Castiel to ask, “Is that for me?”
She quickly grins, tosses it aside, and kisses him before replying, “That one isn’t.”
Five minutes later she lies on the bed with him arched over her, her bright blue silicone cock buried inside his ass, and she rocks into him with slow, lazy thrusts, watching his mouth fall open and his eyes glaze over.
It’s better than her fantasies by far - not least because she hadn’t thought much about angelic energy levels before - and she relaxes into the thought of fucking him as long as she wants; whenever she tires, or whenever he comes, she can pull out and set him to work between her legs - and best of all, with his refractory period, she doesn’t have to feel guilty.