In English, people like to address their close friends with the word mate or bro or buddy. And there is a Chinese word for that.
gēmenr
哥们儿
mate/buddy/bro
Gēmenr, gàn má ne?
哥们儿,干嘛呢?
Hey bro, what are you doing here.
Wǒ yào hé jǐ gè gēmenr chūqù.
我要和几个哥们儿出去。
I'm going out with some of my mates.