All you need to know about this series is that the doc is titled "The Sex Buddy Fic". A series of 'made-them-do-its' which ended up telling a much bigger story.

It took Xanxus two years to bring himself to Japan to visit Hibari instead of waiting for Hibari to come and visit him in Italy. Two years and the realization that he wanted more from their relationship than spontaneous visits that began with destructive fights and ended with them bloodied in bed. Once there, things that have been developing over time finally, finally, come to fruition.

A night hunt goes wrong when the group encounters a Qiongqi. While protecting his nephew, Jiang Cheng is hit with poison by the beast. They don’t have time to research an antidote, but prolonged dual cultivation with another cultivator will neutralize the poison... When he’s chosen for the job, Wei Wuxian is surprised, and determined to give his shidi a good time. Alternatively: In Which Yunmeng Recon Happens While Wei Wuxian is Balls Deep In Jiang Cheng.