Read the original fanfiction here:

https://archiveofourown.org/works/58446625/chapters/148878772

His hands brushed over what seemed like soft sheets on a mattress and then immediately came to a brusque halt when they touched something unmistakable.

Skin. The bare skin of someone's hand just mere inches away from him. His eyes flew open and the sight they were met with shocked him frozen.

On a nice bed, covered in sheets finer than anything he ever owned in his mortal life, resting on a pillow so close he could feel the warmth seeping from his body, was Xie Lian. Asleep, relaxed, a soft smile adorning his slightly parted lips, Xie Lian was sleeping with a peaceful expression, something that Wuming hadn't seen on him for many long years.

or: Hua Cheng and Xie Lian both fall victim to the memory monster. A barely out of Yong'an Wuming wakes up next to pre-third ascension Xie Lian and doesn't exactly know how to deal with that.

https://archiveofourown.org/works/58446625/chapters/148878772