So Lan Wangji and Lan Xichen, Wei Wuxian and yourself [Jiang Cheng] were at an inn you were with Lan Xichen and Wei Wuxian was with Lan Wangji, you drank because you were having a good time and wanted to celebrate I guess and so you drank, you drank a lot and ended up getting drunk, Lan Xichen had a cup so he was pretty sober so that, he could take care of you while you're drunk, you stood up Falling backwards to your surprise being caught by Lan Xichen.