Luke is astonished anew, every time, at how well they fit together. Not just their bodies, but the way the Force itself seems to tug them closer: weaving them, light and dark alike, into something more than themselves alone.
Of course, there's a reason for that, he thinks with a wry smile.
He had brought the revelation of their kinship to Leia like a sacrifice laid on some primitive altar, blood paid for blood, and offered her the knife to make the final cut.
She had refused.
I've lost my world, my family, too many friends to count, she growled as she rode him, the stars of Endor's night sky a savage halo behind her. I won't lose this, too. I won't lose you.
And so the words brother and sister have gained the status of his aunt's dowry plates--treasured things too fragile for everyday use, only brought out from their protective wrappings on solemn occasions, or for rarely-seen guests. With each other, with Han, they are just Luke and Leia, and there is no need for anything more than that--not even words, on nights like this one.
Luke's hand has crept under the waistband of Leia's sleep pants as they sit together on the bed, her back pressed against his chest as she reads to him from some report or other. It's important, it must be, or she wouldn't be bringing it up on this rare evening together, but the only thing he can concentrate on is the spice-and-flowers scent of her hair as he trails kisses down her neck, the only sensible thing in the universe is the way her breath catches when he slips a finger inside her.
There is a wealth of poetry on Tatooine, both filthy and sublime, about just such a moment. Any source of moisture in a desert is to be celebrated--doubly so if you were the cause of it.
All thoughts of meter and verse escape him, though, at the low sound she makes as his finger slides out to spread that wetness, tracing around her clit in ever tightening circles. What better poetry is there than her purr as he finds his mark, and her hips tilt back just so against his own in promise of things to come?
Han chooses that moment to return from the fresher, shirtless, hair damp from the shower. He hovers in the doorway as though still uncertain of his welcome after all this time, until Leia reaches out a hand to him in silent invitation, and he crosses the distance in two strides to take it in his own.
He kneels before them as a supplicant might before a shrine, hands trembling as he assists Leia in pulling off her pants and underthings. Luke never ceases his lazy stroking during this process, and when Han bends at last to his appointed task, his mouth meets Luke's fingers just as often as it does Leia's sex, suckling her juices from both indiscriminately.
If she were anyone else, Luke might call the sound Leia makes as she clenches around his fingers a sob. But Leia is Leia, and she half turns in his arms to stifle any further noises in a desperate kiss.
Leia's orgasm ebbs at last, as it must (Luke wonders sometimes if her pleasure would consume the entire galaxy if it did not), leaving her relaxed in its wake in a way that Luke has never seen her allow herself to be under any other circumstances. Han crawls up onto the bed to put an arm around them both, nuzzling into Luke's neck, the giddy smile on his face a sure indication that he's already found his own satisfaction. (Despite most people's assumptions to the contrary, Luke was far from inexperienced when he joined the Rebellion--what else is there to do for fun on a backwater planet besides fuck, after all?--but he'd never imagined anyone could climax just from giving oral pleasure. Not before he knew Han, anyway.)
Soon enough, Leia will revive, pin Luke to the mattress, and see how long she can ride him before he begs her to let him come. Or Han will come down from his high and want a taste of his other lover to try yet again to decide which flavor he prefers. Or perhaps the three of them will simply keep holding each other, as they're held by the Force, in this small and sacred space carved from stolen moments and unspoken words.
Whatever happens, it will be enough.