There is always room for a refresher. Lan Wangji, of course, has a good memory and generally doesn't need to be told things multiple times, unlike Wei Ying who often forgets things like how he offered to carry Lan Wangji when he had a broken leg.

Still, he is not really serious, though he reaches over to try and pry the pillow off of Wei Ying's face.

He could sing a song for him, but he has only ever really sung the one song for Wei Ying, and after a long pause he yields to Wei Ying's request and hums it, though slowly as if humming a lullaby.