Dark. There’s nothing else but dark around him.
It’s not like Castiel described it, after he was possessed by Lucifer.
It’s nothing like Sam experienced either. There’s no pain, no torture, and he’s glad, he is, but somehow, he would have loved to feel the pain, too. To be able to come back to Sam and tell him that he can understand a little more - not perfectly, sure, but a little more.
But there’s no pain. Just dark.
He has no idea how long Michael had been inside of him - or maybe he’s the one inside of Michael ? He doesn’t know. All he knows is that he wants to get out. He wants to get out!
"Sam! " He yells again, for the hundredth time probably. He doesn’t care. Sam, it's always been Sam, from the very beginning. Sometimes, he can’t even believe that he lived four years without his brother. Four years of loneliness, of emptiness, without his brother, the other part of his soul.
He yells Sam’s name because if he has to chose his last word, he wants it to be Sam. The only one that ever matters.
"Dean? It’s a nightmare, wake up please "
It’s Sam voice, but he won’t fall for it. Michael is doing this to him, trying to make him believe that Sam is here, with him, when he’s truly alone.
Alone, in the dark, in the empty, in a body that isn’t his anymore, with a mind that tries to trick him. It would be so easy, to fall for it, because if there’s one thing Dean wants, it’s to see his brother. Just one time. One last time.
"Dean, please" Sam is crying now, and even if he knows that Michael is the one doing that, pretending to be Sam, he can’t help but feel tears running on his face - on Michael face ? Maybe. Is he crying right now? Is he feeling what Dean feels? He hopes so.
Then there’s a song. It’s Sam, his sweet and soft voice rocking Dean as he starts singing You are my sunshine. It’s not their mom's song, nor their dad's, no. It’s the song Sam learned when he was 5, and that he kept singing to Dean. It was a pure, innocent, and full of love song that Sam couldn’t stop singing, because it was his way to tell Dean that he loved him, that he needed him.
He feels lips against his eyes, and it feels too real. He yells, begging for Michael to go to hell, the touch becoming more and more real, and he remembers the first time Sammy kissed him, the first time they held hands, their first time, the pain when Sam ran away, the proudness, too. He remembers everything, from Sam first word to his last - the same word, again and again "Dean", because what else was he supposed to say ?
He opens his eyes, the light from the ceiling burning his retinas.
Sam is here, on top of him, his whole body spread beautifully on him, his hands holding his face.
"Hey Dean" Sam says, pushing the tears away "You were having a nightmare. But it’s ok. Michael is gone, alright ? It’s just us. You and me"
"You and me" Dean repeats
"Yeah" Sam laughs, kissing Dean’s wet lips "Just us. You’re safe, I promise"
He doesn’t know if he believes him, doesn’t know if he’s really here, but it’s alright. Because this ? This is as close as heaven as he can get. The dark is gone and there’s just love around him now. Who cares if it’s real or not ?