At least he understands when Lan Wangji calls him his. It had been a long journey to get here, and Wei Ying welcomes him with kisses and laughter; this is what he wants to come home to every night. There's no room for sadness here, no worries. All of them fade away, carried on currents of his sweet husband's voice.

And so, he tries to get them home, and he takes two steps, one after the other...

...And pitches forward, tumbling onto the ground, but with his hands up in the air to keep Wei Ying from falling.

Which means he's fallen right onto his own face.