Descriptive of a person with personal issues involving mood swings, unpredictable disposition - similar to those caused by bipolar disorder or schizophrenia.
Him/her? Seems nice, but is riding the bipolar express...one day she'llhug you and the next day bite your head off for no apparent reason
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi