I feel like even if you had never done this fight tanking that you would at least have an intuitive sense of how to tank the boss, from I dunno, maybe a dps perspective. A big part of tanking is understanding and having a strategy, and to that extent, even for you LFR people, there is no such thing as being a casual tank. Being casual means the group dies, you get flamed, and get kicked. I don't like that they couldn't be patient, but then again its LFR- people want to run and be done fast, I've been there. I've been there as a dps, trying to establish order and fight getting kicked. The only reason I don't is because I'm top dps so people listen in the vaguest sense. LFR is not punishing enough to quit however. So do your homework so you don't get yelled at next time, step up and be the authority for your raid. That's why we have LFR, is so people have a space to do that, and eventually become better raiders.