A/N- I write ficlets on Tumblr, so I thought I'd upload some to make up for the lack of regular updates. This one's been edited/had stuff added to it since I first posted it on there, but you can follow the link on my profile to find more of a similar nature (or even request one) if you like.
Only the words are mine; the idea is from a ridiculously heartbreaking headcanon post by 'dancingdogsandbears'.
The first time it happens, Dean more or less has a breakdown.
"Dean?" Cas says. He tries to rest a hand on Dean's shoulder, but every touch seems to make it worse, and so he forces himself to stay away. He sits nearby instead, crouches down by where Dean has slumped against the wall, and watches with pained eyes as Dean's breath comes out in quick, unsteady gasps.
"Dean?" he says again. "Dean, calm down."
It's the wrong thing to say, but he doesn't know the right thing. It had been Dean who pushed aside the gap that always seemed to sit between them like a physical presence, Dean who killed the demon they'd spent days hunting and then grabbed Cas' face in both hands and made him forget that there even were such things as demons. That had felt like the right thing- to Cas, at least- but clearly, it wasn't.
"How can I?" Dean manages to get out.
"What's wrong?" Cas asks, trying to understand.
"I didn't- I, I'm not- if Dad ever-" And then he's cut off by a breath that's much closer to a sob. Cas runs a finger over his own lips, still tingling from the sensation of being pressed against Dean's, and wishes more than ever before that he knew how to deal with 'people'.
"Take it away," Dean's saying, and it takes Cas a second to realise what he's asking. "Please, Cas, just take it away."
"Are you sure?" Cas asks uncertainly. He doesn't want to. The initial ecstasy, the rush of sheer joy he had felt has long since faded- curled up and died when he watched horror flood Dean's face- but that doesn't mean he wants this moment gone.
"Please," Dean says. He looks up at Castiel and their eyes lock, and Cas can never say no to Dean when he looks at him like that. And so he nods once, places his fingers against Dean's temple, and takes the memory away. He keeps it in himself, tucks it away with his own, and decides never to mention it. It hurts to look at Dean afterwards, but watching his smile just minutes later is more than enough to make the hurt worthwhile.
The second time is harder, because Cas sees it coming. It's another close call, another near death stopped only by an in-the-nick-of-time rescue, and when Dean's mouth closes on his, Castiel lets himself hope that, maybe this time, it will work out.
He should have learned a long time ago not to hope. When he takes the memory away a few minutes later, he vows not to let it happen again- if not for Dean's sake, then for his own. Seeing Dean like this, watching him plead for Cas to blot out the memories that burn brightest of all those in Cas's head- it hurts.
He fails. It happens a third time, and guilt stabs at him even as Dean's thumb brushes across his cheek. He shouldn't be doing this, not when he knows what always follows. It's some consolation that Dean seems slightly less affected afterwards, but not enough for Cas to forgive himself.
By the fourth time Cas is shamed and saddened and jaded, but the sensation of Dean pressed up against him is still enough to make it worthwhile for a few seconds. When Dean pulls away, he's as afraid and angry and conflicted as usual, but there's something else there. Something different.
"I've done that before," he says shakily. Cas just stares. "Haven't I?"
"You have," he answers.
"You wiped my memory?"
"You asked me to."
Dean nods once then looks up at Cas with the same eyes as always. When he speaks he sounds so young, so frightened. "Do it again."
And so Castiel does, and it goes on.
The fifth time is the same. The sixth time, he finally manages to get a hold of himself and push Dean away, but the other man looks so hurt- so lost- that Cas forgets to do 'the right thing' and kisses Dean himself. The aftermath is bad that time, awful, and it's almost a relief to make it all better with a simple touch.
Castiel doesn't understand why he keeps letting the kisses happen when he knows how badly it hurts Dean afterwards. He reflects that he really does need to learn to say 'no' to Dean Winchester, but it's a difficult task- especially when he doesn't want to.
"That's happened before," Dean says again, after the seventh time.
"Yes," Cas answers.
Dean shakes his head. "Son of a bitch," he mutters to himself. "I forget, don't I? You take it away?"
"But you remember?"
"Yes," Castiel admits. "Does that bother you?"
"Does it bother you?" Dean asks, looking him in the eye. Cas holds his gaze as he answers.
"Then you're a better man than me," he says. "But then again, there's nothing new there." And he asks, because that's what he always does, and Cas makes it better, because that's what he always does. That's his job.
Castiel hates himself for letting it happen time and time again, hates the heaviness of the one-sided memories he's lugging around with him, hates the day he first laid a hand on the screaming man in the torn leather jacket. He does not- cannot bring himself- to hate Dean.
Eight, nine, ten. The eleventh time, Cas presses his fingers to Dean's head and takes it away, and it's only hours later that he realises Dean didn't even have to ask.
It's only after the fourteenth time (Castiel could never lose count) that Dean seems calm afterwards. Cas can still read the fear in the tensing of his muscles, see the battling in the flicker of his eyes, but he doesn't cry or punch anything, which Cas thinks might be progress.
"- happened before," Cas finishes for him. It's wrong of him to be impatient, but he has done this too many times now. "You ask to forget, every time."
"I remember now," Dean says. "Cas, I- I don't want-" He's struggling to get the words out. "I don't know what to do," he says eventually.
"It's your choice," Cas says softly, because he knows it to be true: there is always a choice, in everything.
There is a long silence, in which Dean seems to say a thousand things, but none of them out loud. Cas wishes Dean would let him know what he's thinking, but not even an angel can believe in a miracle that extraordinary.
"Take it away," Dean says eventually.
"Are you sure?" Cas checks, his own heart sinking with a leaden thump. He had thought that maybe this time… but no, Dean is nodding. Dean is nodding, and Cas really ought to know better by now. He thinks maybe he is starting to understand 'people' after all.
"If that's what you want," Cas says, but he can't hide the ache in his voice.
"It's not," Dean says, "but do it anyway."
Cas hovers- confused, torn- but Dean grabs his hand and pulls it upwards, and so he touches his fingers lightly to Dean's forehead and wipes the slate clean.
Times fifteen and sixteen are near-identical- though the gap is longer, Dean's conflict quieter but greater. The guilt is so overwhelming now that at times Castiel finds himself deadened to it, hates himself too much to even be disappointed in his actions anymore. Cas wonders if it would be better if he forgot as well as Dean, but he can't bring himself to let go. Times seventeen and eighteen occur on the same day.
The nineteenth time, they're sat in a cheap motel. Sam's lost, stolen away by the vampires they're hunting, and it's not easy to find him. They will- hours later, they find the nest and get him out alive and safe- but they don't know that, and they're starting to worry.
And so Dean has kissed Cas and Cas has kissed him back, and Dean has remembered and asked and Cas has agreed. He's raising his fingers when suddenly Dean raises a hand and hits Cas' away. Castiel blinks.
"Damnit, no!" Dean says, frustrated. He stands, turns and walks a few steps away. "No, okay? No."
"Dean?" Cas says, moving towards him.
"Eighteen times before this?" he says, spinning back around to face him. "Really?"
"And you… you remember each time? All the time?"
"Man, how does it not drive you insane?" Dean demands.
Cas nods again before he realises what he's doing, and then struggles to think of a valid and comprehensive answer. Dean's looking at him when he touches a hand to Cas's arm. It's the first time he's touched Cas properly 'afterwards' and the sensation is electric, somehow even more meaningful than the kiss.
"Eighteen times…" he says again, shaking his head like he can't quite believe it.
"I'm sorry," Cas says. Dean looks taken aback.
"For what?" Cas tilts his head to the side slightly, wonders if he's misunderstood something. "You've done nothing wrong, Cas."
"I'm sorry," Dean says, and Cas knows the words burn his tongue; knows they're hard to say, but also knows that he means them. Cas doesn't understand why, doesn't know what Dean thinks he's done wrong- only knows that he will forgive him for it, that he already has.
"Don't be," he answers. And then Dean kisses him again, harder than before but somehow less desperate, like this time he's not afraid of it being torn away. Cas slowly lets his arms fold around Dean's waist, cautiously lets himself wonder if this will be the last first time.
But when Dean pulls away he looks scared, looks in pain. Cas can cope with many, many things, but seeing Dean in pain is never going to be one of them.
"I can take it away," he offers, forcing the words out.
"You'd seriously do that for me?" Dean asks. "Again?"
"I'd do it again," Cas says, and his heart is falling with a heavy thud, his body crumpling- but Dean isn't saying yes. He looks like he wants to- looks like he's going to- but he doesn't.
"Don't," he says instead. "Don't you dare."
And there's fear in it- more than fear, flat out terror- but throwing fear into action has always been the Winchester way. When they kiss again, Cas thinks the moment might just be unforgettable.