Julai is a term used against gay men with the top sexual role in anal intercourse or in general for homosexual men. Probably related to that this expression also had the meaning of stupid, imbecile, unwary, despicable man or victim of theft or fraud. As on other occasions, to homosexual man is supposed all sorts of defects so it is possible that there has been a semantic leap and has ended up being used as derogative slang for gay people, as happens for example with the word Duck.
Variations: Jula, Julay, Julandra, Julandras, Julandrón.
Read more: Pato. Gay Dictionary: (Latin America).