Xu Qing didn't know how Jiang He slept, but he himself had a very comfortable night's sleep and woke up when it was broad daylight.
As for the spring mattress being uncomfortable... that was only when one person slept on it uncomfortably. After lying on the bed that Jiang He had slept on for a long time, it was akin to one and a half people sleeping on it.
Xu. Pervert. Qing was extremely satisfied. When he woke up, it was nearly nine o'clock, an unusually late hour by one hour for him. Jiang He hadn't disturbed him, which seemed to be an unspoken agreement they always had—no one would wake the other in the morning.
Probably because when Jiang He first came, Xu Qing would sleep until nine or ten o'clock; that habit formed then. Later on, he started getting up earlier, but they still never called each other to wake up.