I was trying to describe what I feel is the best place to position Anantaboga to a friend last night (over IRC, so we had no visual aids). I was looking for a video and I was shocked to find that there aren't any showing the positioning I like. It's so much better than the ones people use that lets the tail swipe affect some part of the room. Next time I go I'll have to take a screenshot.
There are two ways I've taught tanks to do it, and both are easily explainable. One that I think you are failure with is having the tank back up against that little piece of broken wall on the outside edge. You can go and stand there without agroing the boss to show them. Pull the boss directly to that, wait for it to get to you, then run directly though the boss just a little past the statue. Makes it so the tail is in the wall, and gives a nice cubby for dps on the other side. Also got to remind him to not freak out if the boss full stops for a tail swipe during the turn, it may happen, but doesn't really mater.
The other way, that seems easier now, is just having the tank run right to the boss from the entrance, while throwing shit at him, all the way to the back wall. Wait till the boss catches up as he might tail swipe when he turns, and then running to the corner. It is easy because if done properly, the tank will not have to move at all ever, and the dps and healers can all just hang out behind that last statue for the full fight as well. Other then to kill adds and when they get the bomb of course. The only trouble it causes is that the tail will be facing in the direction of the first add statue, but really that isn't much of a problem.