[Petrusha]

Tested after 1.11...
You know. Odd grps go left, even grps go right. Each side has this spot.
Well at wall, closer to spot where onyxia is being tanked, you will find that mountain (or wall or rocks or watever) that has spot where its not high. Over there stand near it (it looks a little bit, like corner), facing whelp caves and jump on the wall. Now u cannot be feared down and be damaged by fire in floor at phase 3. It is prefered to be used by those who dont do dps while tank gets agro. If you overagro on that spot, onyxia will get avoid buff which will wipe all grp. Also it does teleports you off up there to onyxia sometimes, but u can get back any time u want.

[lvlrbojang1es]

If you're having enough trouble to the point where this glitch is necessary, i don't think you would even want to risk the fact that she goes into evade bug very easily.

Although this spot is almost "common knowledge" to anyone who is doing onyxia, a good post none the less.

Somthing more to add on this:
During deep breaths if you stand at the enterance to the whelp caves (the part where the floor dips down a bit to make way for the whelp cave enterance) you can completely avoid any deep breaths. Be careful to not get too close to the whelp eggs though