Mis huevos

Mexican slang. Literal translation is my testicles but it’s used by men and women. It can be used as a swear word but also to swear on something that’s a matter of great importance, ranked somewhere between merely promising something and swearing something on your mother as it’s your testicles or the next best thing you’re putting on the line. As a swear word, it can simply be used to discredit someone who just said something you find silly and hard to believe. In the same sense, the person uttering it is also suggesting to some extent that something is so uncredible that they might as well put their balls on the table.