Blue yan means:

1. Blue face is derived from red face. At present, words widely used on the Internet usually refer to women's names for male confidants. Because of the particularity of men and women, it is called a "fourth emotion" which is separated from affection, love and friendship.

2. Blue face exists as the "fourth emotion" besides affection, friendship and love. It is the most stable warmth, close but pure. This state of under-lover makes people more relaxed. Many topics and emotions that can't be shared with lovers can be deeply communicated with Lan Yan. In front of Lan Yan, you can be presumptuous, coquetry, disregard the image and be yourself.