Well, it took a while, but my promised Han/Chewbacca fic is here. It's semi-explicit, I suppose? Nothing detailed is contained within, but there are a few paragraphs of smuttier stuff.
One day Han Solo wakes up and realizes that only one person has stayed by his side. No, that's not true, not accurate at all. It does a disservice to everyone he's left, to everyone he is still running from. A better way to put is that there is only one person that he's let stay. He doesn't know why.
It's not like he's lacked for people to care about. He loved Lando, when they gambled and drank and fucked, before he knew how to tell someone he felt and resorted to using his hands instead, trying so desperately to convey meaning with the press of callouses against bare skin.
He loves Leia, his heart captured thirty years ago in the metal and plastic bases of their enemies, trying and this time succeeding to show her what he feels, pushing his emotions past a façade so convincing he himself forgot how to bring down the wall. He spends countless hours at the helm of unfamiliar ships wondering if she could ever forgive him, trying to decide if he even deserves it.
He's not with them now. It aches. It's his fault, he knows it, but that doesn't make it hurt less, doesn't make the days go by faster, doesn't stop the thought of Leia's smile from bringing a dagger to his ribs.
There's only one person who can draw it back out, healing his flesh if not his heart, and that is Chewbacca.
They live in their own world, a bubble in space where Han is the only one who knows what Chewbacca is saying and Chewbacca is the only one who understands what his words mean in turn, an arrangement cemented by every seedy bar and dirty hostel they find themselves in. Their trade is something he could never afford to lose, not with that sword dangling over him for all eternity, or at least what feels like it, because Han Solo the smuggler will never know what forever feels like. He won't even get close.
Only with the Wookiee does Han let himself relax, his shoulders lowering from the stiff position he finds them in at the end of every day. And, for his part, the human is the only one who can make the Wookiee laugh.
A lift debt, what's in a life debt? Han wants to lift it, although he doesn't really know how. He doesn't know if he can. The way it's been explained to him is that Chewbacca's pride, his whole status as a person worthy of respect, rides on this, that it's not something he has done lightly. Still, Han doesn't like it. He wonders if Chewbacca has a sword of his very own hanging over his head.
It comes to him out of the blue one day that the Wookiee could hate him for dragging him away from his life, from all that he's known. The thought brings that dagger of his crashing down. He leaps out of his seat to avoid it, stumbling over the buttons and levers for a ship he doesn't care about. He feels foolish a moment later for reacting to so strongly to an idea. Then it strikes him, the reason he is acting so strangely, the fear festering behind his actions.
He cannot lose Chewbacca too.
He has let too much of his life go. He thought he wanted the Falcon more than he wanted a Calrissian, and now he has neither. He thought the only way to deal with losing Ben was to leave, but now his family is shattered and he holds the stone that broke the glass.
All this is running through his mind when he kisses the Wookiee.
He has spent half his life with Chewbacca. He knows him as well as he knows anyone on this world, any world, the ship they stand on while Han has Chewbacca pulled down by his shoulders so he can enact what some might call another method of self-destruction. If that's what Chewbacca thinks of it, he doesn't say. All he does is kiss back.
It's awkward rustling in the sheets at first, trying to figure out which bits go where. Chewbacca has never been much of a comedian, but they can't help but pause to exchange a grin or two, the first ones Han has genuinely had in what feels like a lifetime.
Then, in a shift neither of them could identify if asked, they shift from laughter into seriousness, his hands sliding into Chewie's fur deep enough to feel the warm skin underneath. Han is older than he'd like to be, but warm palms on his sides steady him as he shifts. His heartbeat is racing; so is Chewbacca's if his panting is anything to go by.
There's heat and friction and fur between his fingers, a twist in his life that dredges up a few last bits of happiness for him, his eyes fluttering shut as he thrusts. He feels like he could do anything in this moment, fix anything, be anything. He could do the Kessel run in 10 parsecs, even. He could piece together the fragments of his life.
It doesn't last, but in that moment and the next few that follow, he finds that it doesn't really matter.
Nothing really changes between the, not after the first or the second or the third time. He didn't really expect it to. If anything really is different, no one in the galaxy can tell except for them. After all, others only see Han Solo the smuggler and Chewbacca the Wookiee. Even those that know there are swords over their heads cannot read minds, and while Han is the not the only one who speaks Chewbacca's language, they are the only ones who understand each other.