Many people tend to get emo girls mixed up with other stereotypes, like punks, goths, and posers.
Mean emo girls, however, take more advanced measures to bond with. Tell her angst is very attractive and suits her well, and agree with the things she thinks are stupid, unless she hates things that they contradict your beliefs, then move on to another subject.
What you need to do is be nice even if she is insulting you or throwing death threats at you.
You don't even have to tie her up, at least, not right away.
They are far more common at concerts, especially in rock, metal and punk concerts.
They have been known to even appear in churches, not to burn them down but to praise their hidden inner goodness.