可爱萌妹纸的保护色
[kĕ ài méng mèi zhĭ de băo hù sè]
The protective coloration / disguise of a cute girl ('cute girl' often used on the internet to describe lively and attractive girls). Maybe she wants to hide some true thoughts while showing others her lovely and friendly side using such a disguise or protection color as defense, not wanting to be hurt.