since it’s relevant, i once wrote an April Fool’s Day Dean/Cas fanfic:
The Joke Is on You (And So Is Castiel) (4.8k, rated M)
Summary: “O Castiel, who art in Heaven, we pray that you get your feathery ass down here, pronto."
Dean prays for Cas, but for some reason his prayers are answered literally. Now Castiel has an actual feathery ass - and from there, things only get weirder and progressively more inappropriate, until the unanswered question begs to be articulated: exactly what the hell is going on?
i forgot about it until just now (◡△◡✿)

» The Joke Is on You (And So Is Castiel) — almaasi
“O Castiel, who art in Heaven, we pray that you get your feathery ass down here, pronto.”
Dean prays for Cas, but for some reason his prayers are answered literally. Now Castiel has an actual feathery ass - and from there, things only get weirder and progressively more inappropriate, until the unanswered question begs to be articulated: exactly what the hell is going on?
read on AO3

» The Joke Is on You (And So Is Castiel) — almaasi
“O Castiel, who art in Heaven, we pray that you get your feathery ass down here, pronto.”
Dean prays for Cas, but for some reason his prayers are answered literally. Now Castiel has an actual feathery ass - and from there, things only get weirder and progressively more inappropriate, until the unanswered question begs to be articulated: exactly what the hell is going on?
read on AO3