It is a figure of speech used when sarcastically trying to say oh really mate? If someone uses this on you, you must reply with Ma or Ha em as it shows respect to the other person and asserts dominance over the other person. Ha em is also used as a reply because the phrase oh em originates from oh Emma. Specifically Emma Watson the absolute reason why boys simp
The extended version of OMG (oh my god/gosh/goodness). But, you may be asking, doesn't extending an acronym in text talk defeat its purpose? Yes, yes it does.