It's a mexican slang that has 3 meanings:
1. it's a vulgar or informal way to say "you're kidding"
2. it's a vulgar way to say "stop messing around"
3. sometimes can be used like saying "no way"
4. or when you're scared or desperate and you suddenly say "no mames" just because nervous or something like that and when you say that word is like saying "damn".
guy1: Karina said that you're going around with Jose
girl1: no mames !!!
comes from the word mamar, meaning "suck" in spanish.
Mexican slang for : "you're kidding"
Mexican slang for : "Stop messing around"
guy 1: Yesterday I saw Madonna in my back yard
guy 2: No mames!
guy 1: Maybe you can dress in drag...
guy 2: No mames...
mexican slang for fuck off. polo polo says it a lot if you want the correct pronunciation.
girl: i love you
dude: ya no mames cabrona
Stop sucking cock fucken bitch
Bree said "where's david" and Gus said "No Mames cabrona"!