I made this Rubbery Flank farming guide to help out players who want to farm meat instead of buying them from the Auction House. I decided to search for places with a high density of mobs which I can kill and drop Rubbery Flank. I traveled around Nazjatar, and after a while, I made a list of places.
Nazjatar - 1
There are all kinds of Snapdragons around the marked area, all of them drop Rubbery Flank. A lot of them are elites, but they are pretty easy to kill if you have decent gear.
If you haven't finished the Snap Back quest, then you should pick it up from Collector Kojo. You will get a scroll from the quest that allows you to kill Elite Snapdragons much faster. So if you don't turn in the quest, you can drastically increase your farming rate.
Nazjatar - 2
When you first go to this area, there will be a lot of Nagas there, but once you kill all of them, they won't respawn as fast as the Savage Snapdragon. It seems there is always at least 3-4 Savage Snapdragon at this area, so once you cleared the Nagas there will be mostly Snapdragons there. They are a bit spread apart so you have to move a lot, but this is the only other place where you can get Rubbery Flank.