<blockquote>Lan Wangji looks down at his own hands, steadying himself. It is easier to think clearly when he is not looking into Wei Wuxian’s eyes. He takes the scroll from his pouch.
“Research has uncovered a method,” he says. He does not mention the forbidden hours and nature of said research, nor does he elaborate on the method itself. He will not venture to speak it aloud. He hands the scroll over.
Wei Wuxian looks at him for a long moment as he takes it, and Lan Wangji holds his breath, waiting for him to decide. Waiting to see if he is at least interested enough in the possibility of a new core to read it.
He is. He does. Lan Wangji might be relieved, if not for what comes next.
Lan Wangji offers to help Wei Wuxian develop a new golden core via dual cultivation. He struggles to keep his feelings in check.</blockquote>
Fwb (where the benefits are dual cultivation)