How do you use 'ge' or 'gege' in Chinese/Mandarin?
I know that it means older brother but it's for both genders right? Like a girl can call her older brother 'Luhan-ge' and a boy can call her older brother like that too. Is it only for real brothers? Wouldn't it be awkward to call your male friend like that?

Question

Answer

It's for real brother and someone older than you ,someone you respect. or in a joking way.
In the office if a senior staff help you done something ,you might say:" 王哥，真是太谢谢你啦！"in this sentence,  ge is just mean to be close.
A famous joke is "信春哥，不挂科" （Believe brother Chun, you can pass the exam）,chun is Chris lee,and she is a tom boy.

Answer

yes, and there's also 兄 = xiōng