A/N: This is taken from the episode "First Born" in season 9. I followed the lines closely, but everything else is a head canon interpretation of the scene, of course! After seeing this scene, and another specific one from later in the episode (which I might write about a little later as well) kind of made me ship Samstiel. I still aggressively ship Destiel, but when the feels get to you... Sometimes, there's just nothing you can do. So... Here you go! Enjoy!
Cautiousness, at this point, is paramount, but it seems absolutely useless. No matter how slowly Castiel tries to remove the unwelcome grace from Sam left behind by Gadriel, the Winchester still chokes down fits of pain, fighting to remain conscious until the procedure is finished. The blood from Sam's nose gathering along his cheek and jaw creates a sinking feeling within the angel at having to cause such pain for a spell that may not even be successful. Castiel tears his eyes from Sam, needing something else to focus on before he continues to try and remove the grace.
A familiar item on the table nearby catches his attention: the peanut butter and jelly sandwich. The taste of a thousand molecules swimming around in his mouth had done him no pleasure when he took a bite of it earlier. He had been slightly disappointed that since he was no longer human, he couldn't enjoy it. But seeing the simple food item brought a small grin to his lips despite the heaviness of his heart. He looks to Sam before murmuring, "Hold on. This may pinch." He drags the long needle from Sam's neck and the hunter blanches with the extreme discomfort.
"Cas, what the hell-?" With his rugged and broken voice, Sam begins to sit up when he is forced down with two fingers to his forehead. He gasps at the sensation, but feels energy and wellness rush to him all at once. Flinging himself into a sitting position when the force dissipates, he feels about his face and neck.
"Cas, what the hell was that?" the hunter barks.
"I've healed your wounds completely."
"And the grace?" Sam's eyes are large with nervous anticipation.
"Well, whatever grace was inside you is gone now. What's left of Gadriel is in here." Cas carefully places the needle with the grace into a box marked with a sigil. "We'll just have to try the spell with what we have." Cas feels the mood of the room darken almost immediately with Sam's disappointment.
"Damn it," the hunter whispers.
"Sam," Castiel begins, "I want Gadriel to pay as much as you do. But nothing is worth losing you," he adds more forcefully. Sam glances up at him almost curiously, his eyes darting once more to the floor before they find their way back up. "Being human, didn't just change my view of food," Castiel continues before his eyes melt into a shape that Sam doesn't remember receiving from the angel before. "It changed my view of you."
Sam's eyebrows quirk with definite confusion and an uninvited breath escapes from his chest. His eyes wander again for the tiniest of moments, but anticipation quickly drags them back to focus on the stunning angel in front of him. "I mean… I can relate now, to how you feel."
"What are you talking about?" Sam asks. Cas opens his mouth and takes a breath before continuing. He steps closer.
"The only person who has… screwed things up more consistently than you… Is me." Sam's face quickly goes through a variety of emotions as he tries to think of what to say. But Castiel keeps explaining. "Now, I know what that guilt feels like." Sam still struggles with words as the angel speaks, but nothing comes out. "And I know… I know what it means to be sorry, Sam." Hearing his name said so sincerely suddenly drags him out of his own nervous and clustered thoughts, but his eyes stay on the floor. "I am sorry." His eyes come back up, and he looks at Cas.
"I know," he says softly. They share a look together before Cas breaks the eye contact for a moment.
"You know, old me…" he shrugs noncommittally. "I would've just kept going. I would've jammed that needle in deeper until you died, because the ends always justified the means." Sam swallows. "But what I went through…" Castiel pauses as he struggles to find the words. But he just grins to himself instead; A beautiful little smile that Sam still isn't quite used to seeing. "Well, that PB&J," he smiles again, "taught me that angels can change. So…" Cas turns to pick up the box containing the needle. "Who knows. Maybe Winchesters can too."
Castiel turns to leave, and the hunter's eyes follow his retreating form. Sam's heart feels very full, and he isn't quite sure what to do about it.
A/N: Should I make a chapter two with the other scene? Definitely thinking about it.