Wikipedia says the term analingus was coined in the late 19th century and my cursory glance at google showed that there were explicit references to eating ass in early modern texts (~1500s). So tongue punching the fart box is at least as old as the Renaissance. Take the precautions you would normally take for butt stuff (disease free, recently bathed, haven't pooped or eaten in 3+ hours, an enema if you're fancy) and you should be just fine. Eating ass is fun and I will die on this hill
I don't even understand the appeal for either of the involved parties. I don't want things in or around my asshole, nor do I want any involvement with those of others. For reasons that completely elude me there seems to have been a cultural shift during my life from butt stuff being deviant behavior and fodder for jokes to almost a default expectation.
I don't actually believe that it is a common expectation in real life dating between actual non-terminally-online people, but it certainly seems to be portrayed as such.
I don't have a high "body count" by any means but I've also never heard of anyone eating ass before the recent internet craze. I'm half convinced that it's just a meme.