The Spanish word "pinche", according to sources is an all-purpose insult enhancer, which would be roughly equivalent to the use of the F-word in English.
It is strongly associated with cursing which is not just isolated to Mexico. Reports say that people from Panama and Columbia also understand that it is used to describe something insignificant.
While "mayate" references a black dung beetle and is a derogatory term used to describe a dark skinned person.
Combining these two words then will give a very clear explanation of what they sadly imply.
While it is part of learning the local Spanish to learn the “not so nice” expressions (swear words and phrases), it is still best to speak nice Spanish words to make your Spanish more colorful. Learn these 40 Beautiful Words In Spanish from BuzzFeed.
Four-letter words have been around since the days of our forebears—and their forebears, too. Check out nine things you probably didn’t know about swear words at TIME.