People say there is destiny and people say fate is unavoidable. He still doesn't believe that. He believes in body memory. He believes in action and reaction. In cause and effect. The one damn trinity of the things he trusts. Trusts above all else, above his own judgment. So maybe there is no such shit in his book as being destined for Hell, but it is a matter of human and beyond human nature to have a sense of belonging. Dean doesn't really want to belong where he knows he does. His body tells him that even if his heart and soul hiss and wail and throw around ash in sad final act of shame and resistance fueled by despair.
He tried to lie to himself, he really did. He's the conman of all conmen and he played his part so well he sometimes believed in his own crap. Maybe that's why in the end, he failed to swallow his own bullshit. It's exactly like with his own dick – he used to tell his mind bedtime stories about his own presumed straightness until his stomach would go numb. It just never changed the fact it didn't really have to take a pussy to make his dick swell. He only needed an extra incentive to have the buried knowledge poke and prod at him insistently until he got both blue in the balls and comparably urgently aware. The nearly constant proximity of Cas and his all too exploitable flesh was a good reminder.
Thing is, however, to this in particular he's learned to say okay to, he's learned to jack off to vivid images of that body his imagination so easily supplies, and he's learned to enjoy it, to mutter Cas's name as he comes and to tell himself he craves it when his own sack of bones still trembles from release.
There's something else he knows it's coming for him and he clenches his hungrily shaking hands into fists and he bites his lips and he gasps when it beckons him to return. It's been calling him for a long while now. The song is loud, so loud these days he very scarcely hears that bullshit lullaby about his so called redemption, if even he does so at all. Cas saved his soul, didn't give him a new one, a tabula rasa. He pulled him out of Hell, but he didn't pull Hell out of him. It's as simple as that. And as he rebuilt his body, he rebuilt its cravings. Even more simple. When Cas laid a hand on him and took Dean out, his body was lost. It missed the instruments it cradled like kittens, it dreamed of symphonies of torture – it was a virtuoso thrown out of orbit amidst the opus magnum composing spree. It wailed and it whimpered and his muscles and joints mourned the loss of their tools. But then he's grown attached to Cas. And he swallowed mouthfuls and mouthfuls of hope and salvation. He almost thought his love and grace washed the taint away from his bones as his cravings went away silent and his fingers became docile, almost sated with the perspective of touching something else.
And it were, since then, only the tiniest reminders that pinched from time to time. And it was easy, so very easy, to let them slide even when they occurred, obvious and gruesome in their message. They were meant to be cramps on the change of weather, nothing more. Because he was purified and saved. So nothing more, he told himself. But he knew and understood nonetheless that his soul was Hell-marred. There was nothing he could do with it.
When he'd get himself splashed with holy water, he'd just cringe in displeasure and do everything to conceal his revulsion because it burned him akin to how it burns a demon – there was nothing he could do with it. It just stung. Because Alastair remade his skin countless times more than Castiel had and his skin simply learned to feel like a demon's would. It welcomed the brand like a dearly missed friend, like a long awaited darling.
When somewhere along the path of his life he stopped seasoning anything with salt. He'd use it to attack, he'd use it for defense, but it would never make it past his mouth. He's forgotten himself once in a shithole in Michigan and after trying his stupid fries he spat out blood for three days. He tried it again in Lebanon, hoping he'd be pure, but he quit on his soup just after he tasted it. Neither Lisa nor Cas could banish that curse and there was nothing he could do with it. He prayed to Cas, crying he was weak and that it's eating him from inside, but Cas's been either at war, or dead, or a god, or silent, or dead again, or brainwashed, or deaf. And in the glimpses of hearing out Dean's cries, he'd soothe him and tell him that he's good and he's strong, but Cas is Cas and Cas is so often wrong.
When Abaddon murmured to him the threats about making him torment, kill and rip asunder, his body was tempted, his mouth gaped and then swallowed its urge back down, need to reunite with his masterpiece kept hissing through his blood, saying it remembered this. He blinked and he saw himself in her place, having all that she has and he savored the sight for a moment until his heart understood what his mind made him crave. There was nothing he could do with it, then. Maybe that's why making sure she's dead is the last fucking thing he dares to want because he doesn't see her face when he looks at her just be, he sees a mirror, a memory of better times. He doesn't want to feel any of this, he wants to be clean again deep inside, it tasted so well while it could still last. But he's been reclaimed, so it's forever gone. He's gonna cry on his knees anyway at some point, saying Cas, just save me again when the stench of blood will fall too heavy on his senses and it will be too late and Cas will fall on his knees alongside him right then and whimper and sob his what have you dones and there's gonna be nothing they can do to turn this motherfucker around.
He knows that's how it's gonna be because left to his own devices, he drove all the way to Corpus Christi to make it precisely that funny, fucking every single willing waiter and waitress on his stops while he was at it, and now he just stands there on the shore, staring into the ocean, thinking that his Blade will come to him out of the water just like his Man and Shield came back to him from the water years before. It's his jawbone and he's an animal and he needs to bite – or at least that's what he thinks he is. It Tara was alive, he muses, she'd get a jolt of pain in her knee if he'd cross her threshold one time more. He decides to be thankful he didn't get to see her skinned corpse, cause he knows there'd be a voice in the back of his hand, telling him he would have done it better and there would be nothing he could have done with it, for it would have kept whispering until he gave up and quietly agreed.

He calls Cas to tell him all of this and maybe a bit more, because he at least learned his lesson not to fucking lie. Cas listens to all of his choked out admissions and the line on his side collapses into the loudest silence on Earth as Dean tells him about the Mark. Dean can only hear the ocean hum and he begins to wonder again when will his weapon sing back to him. But Cas's voice instead makes Dean snap out of it, as he breaks the stalemate and speaks, voice low, sharp, and terrifying in a way that matches Dean's disturbing urges and thoughts.
"Lucifer has marked you, but I've marked you stronger" he growls and Dean shudders. "Come back."
"The hand-mark, it wore off."
"I'll mark you thirty-fold. Just come."
Dean snorts brokenly. "Why?" he decides to ask.
"You said you want me to punch you" Cas says. "I think it's time. Come."
"If you try hard enough, I might."
Cas sighs.
"Dean- "
"I know, fine" Dean cuts him off, aiming to add something along the line of just kidding, but he hears Cas whisper just before he hangs up on him abruptly.
"I will, then."
Dean is back on the road just like that, head on fire, heart filling with some stupid sort of hope, again, and his dick uncomfortably hard, pressing against the inseam of his jeans. He almost doesn't hear the ocean chanting to him.
He doesn't have to. His fingers know one day's he's going to unite with the blade he's taken for his bride and that when that finally takes place, Cas is gonna punch him harder than he plans.
Turns out he's in for a man and angel and bone triangle. There is just nothing he can do with it.