LITERAL TRANSLATION: O.K. ñema means cock or dick. So is basically like the word "mamaguebo" which means "dick sucker". "MAMA" in this case comes from the verb " Mamar" which means "suck".
WHAT IT ACTUALLY MEANS: it is slang for "ma nigga" "yo, bro" (if you're really close) "you fucking asshole" if you're mad at the person.
Some other people that live at your moms or grandma's house. Usually other relatives who are for the most part mooching off the old lady. This term is often used in the African American community.