"I have it on somewhat good authority that it's a thing adults do," Castiel murmurs. "And you will have as proper a birthday I can muster every year from now on."

He lets out a happy sigh, running his hands down Dean's back to grab a generous handful of ass.

"You have two immediate choices before you. Birthday sex or Birthday pie. You can have both but you have to choose the order in which you will have them.