It is not that they sleep together, at least not in the literal sense. Euphemistically, well. It is Gojyo, after all. But afterward the night lies heavy on them both, drenched in the threat of nightmares, and both of them know, face-for-face and scream-for-scream, what they will dream of if they sleep.
It would be easier if being together was enough, but another person's unconscious presence isn't enough to fight away the demons of the past, and more often than not Hakkai ends up death-still except for the tears while Gojyo screams himself awake, raking bruised trails down his arms with nails kept short to avoid the blood, and both drag through the next day shadowed by the memories as much as by the exhaustion.
Hakkai figured it out first. Gojyo gets snappy when he doesn't sleep enough but Hakkai just gets quiet, and after the fifth or sixth or seventh night - even now neither of them can remember exactly when - Hakkai pushed Gojyo's head into his lap, stroked his red-stained hair, and said, "Sleep." Gojyo would have refused anyone but Hakkai, but he would walk into fire if Hakkai asked him and facing nightmares grown familiar if not kinder with repetition is minimal in comparison.
He jerked awake when sunlight hit his face, startled by the heat and the sudden awareness of time passing, and Hakkai was watching him with a half-smile, sad at the edges as Hakkai's smiles always are, but his eyes were happy, shining like they do more and more now when he looks at Gojyo.
It would have been a perfect day, the world clear and shining as it hasn't been in years for Gojyo, except for the flicker of guilt when he looked at the silent driver in the front seat of Jeep, and Gojyo hates feeling guilty for all that he's used to it.
Hakkai tried to fight that night, after he had traced away the aching memories of Gojyo's scars with his lips and Gojyo had replaced his sad smile with gasping pleasure, if only temporarily.
"It's okay, Gojyo." Hand against his face, twining into his hair. "I'm used to it."
"So'm I." Gojyo hates to stop him but he will get distracted if he lets Hakkai continue. He catches the shifting hand, holds it still where it is. He reaches to touch Hakkai's wrist, can't quite cross over to brush the bird-fragile bones shifting under translucent skin with his callused fingers, lets his hand drop to his side. "I did when you asked."
That does it. Gojyo knew it would, that Hakkai's careful sense of justice will win the battle for him, even though he feels like he's killing something beautiful when he watches Hakkai's throat move in anticipated fright as he tries to sleep beside Gojyo. At least it doesn't take long. Physical exhaustion wins out over the mental rebellion and Hakkai drops into sleep, going so utterly still that it takes hours before Gojyo can stop watching his pulse to confirm that the other man is still breathing.
They are almost late leaving the next day, because Gojyo can't stand to wake Hakkai when he looks so relaxed, when the tension in his shoulders is gone and the almost-smile on his face is peaceful instead of resigned and Gojyo can touch his wrists and neck and hair all he likes, as long as he is very careful. Sanzo's stormy entrance pulls Hakkai awake, and Gojyo laughs, sincerity turning the sound into liquid warmth in his throat, at the expression on the priest's face when he sees Hakkai blinking awake without the lingering darkness of nightmares in his eyes.
They take turns after that, trading days or sometimes shifts in one night, and it's not perfect but it's enough. After everything they have done, everything they deserve, neither of them feels the bargain is unfair. Gojyo never tells Hakkai about the feather-light touches he scatters like raindrops across sleeping skin, and Hakkai never tells Gojyo about the kisses he presses into red hair, but they both wake from dreams smiling now, and if they can't remember the content, well, it's the thought that counts.