"I before E except after C".4. Continuously shifting around the target
Truth is, in languages, that saying has no basis whatsoever. Some fights require movement; first boss in the Temple a definite case in point. (And yes, I've had melee DPS tell me to stand still in that fight...) Movement is a thing tanks have to learn to do at some point; minimising the risks and the issues with it is where the skill really lies. Slime in Copperbell is the first real lesson in movement.
Perhaps a better replacement for this situational thing is an actual tip; Tanks, did you know that most of those big AoE cones and circles can be interrupted? It's true! Your stuns can save you damage and your healer some precious mana by interrupting some of the more pernicious moves, such as Aiatar's poison breath. Rather than trying to run out of them, save your stuns for these moments. Every single precious stun counts!
Plus if you're interrupting, then you don't have to move. Hey, it's a win-win!