Castiel yelps, in surprise and delight, when Sam smacks his ass, jostles the plug, and only widens his legs so he can show his enthusiasm. This is just what he wants, just what he needs. Sam, all over him, so that Castiel can feel nothing else on his skin.

He breathes through the strokes, moans and grunts occasionally, but never just in pain. By the time they've managed 20, Castiel is panting heavily, catching his breath and listening into himself.

"Green," he finally decides. This is nothing but good. It's not yet enough, though - and he knows more awaits him.