Used to describe the irrational, spontaneous and extremely anti-social and negative behaviour often displayed by 'emos' and 'scene kids'. Can be extended to people outside this idiom, in which case the inferred intensity of the 'emo bullshit' can vary greatly depending on the context. Can also be applied to objects.
My girlfriend ebsed last night and wouldn't tell me what the fuck was wrong.
My computer's ebsing, and won't load itunes.
I can't put up with any more of her ebs. It's her set of issues, not mine.