That night, he sneaks out of the master bedroom after Su Xueyi falls asleep, and into Han Yu's room.
He finds him asleep on his front, with the covers thrown off, both arms wrapped around his pillow.
Softly, Xi Zirui climbs on his back, and drops butterfly kisses all over the smooth expanse of his back. He wants to see how many times he can kiss Han Yu before he wakes up.
Not many, it turns out.
"What is gege doing?" he asks, his voice muffled by the pillow.
"Taking advantage of you while you sleep." Xi Zirui lowers his head to drop a kiss between his shoulder blades. "Isn't it obvious?"
Han Yu lets out a pleased hum and yawns into the skin of his arm. "That's all? Then by all means proceed."
Xi Zirui giggles, his next kiss has some bite to it. Han Yu shivers into the feeling of Xi Zirui's teeth dragging over his skin.