What's with the word "mf"?

Recently I have witnessed lot of online communities use this word casually, but it gives me chills to even think of that word and what meaning it has. Like even for casual talks a person calls his friend mf, like what the actual heck.

Is it me running out of the trend or is it a cultural thing right now? Because honestly saying mf for everything just makes me puke

Are any women here feels the same way when these words used around? And let alone those words like behenc**d stuffs for fun