Lingyue and Younai

Show her a reliable and mature side, try to help her shed her "little adult" shell.
Actively thank her for her care, so she feels her efforts are worthwhile.
Gently accept her when she acts childish or shy.

Play with her and keep up with her lively pace.
Take her opinions seriously, don't be perfunctory.
Don't break her "acting like an adult" facade, indulge her occasionally.
When she accidentally shows childishness, don't laugh at her, but silently protect and accompany her.

This is my first time using multiple characters, and also a character setting I agreed to help write.
Feel free to give it a try!