Ah, Zuma means aunt or sister-in-law If you are married but still young, you will call him angrily. )
Mu Tong is a direct translator, which means that people who do the same thing are a bit like colleagues, but unlike colleagues, students can also call each other "Mu Tong" as LZ said.
Moreover, Mu Tong appeared as a Korean in China, and as a Korean wave in South Korea, which was not so useful.
Mu Tong is a bit like the comrades China used to call each other.