Lan Wangji will tell him of the game once they returned back to their bedroom.

"Mn. A collar. But made for people to wear, and not for pets. When I look at you, I felt something missing." It was meant to be a type of fashion, which he noticed people are wearing. But a part of him wanted him to wear it as a symbol that he belongs to him as a tangible reminder.

"I like both, so why not take those and try it on? I think those two will look good at you." The bells is a nice addition, so he can hear him as he walks around. "But I like the one with the bell."