Inappropriate Use May Result in Strange Side Effects (слэш)

In PIDW, there was a certain legendary cup which when used to make tea with even a single thread of another’s hair or a drop of their blood switches bodies with the person who drank it. It turns out… if you don’t use it appropriately it’ll either not work at all because it has no target, or will swap you with your soul mate.
Too bad Luo Binghe had no idea about that. He was just going to drink tea and somehow he found himself in Shen Qingqiu’s body, staring at his own sword mound. Oh and what the absolute hell is the ringing in his ear?