Short for "feral mexican" and refers to guys who use who use trivial reasons or incidences as an excuse to approach girls and attempt to hit on them. The term has its origins from an incident whereby a male didnt read a sign and tried to open a locked door in a mexican restaurant. He then leveraged off his embarrassment by using it as an excuse to go and talk to a table of 3 attractive girls who were clearly unimpressed. Conversation of a fex mex often does not extend beyond the aforementioned trivial incidence or excuse as their only angle is to attempt to be funny and novel.
Noun: That fez mex just tried talking to me again.
Verb: I just got fez mexed when I was having coffee before.