Don't you need to be facing Malygos to be able to cast the dps abilities on him though?
No you don't.

I'm glad I asked this question on here! It seems my issue with this seemingly crazy hard phase 3 is actually VERY simple
I agree. When someone told me about this one button Malygos method and tried it the first time. Suddenly Malygos phase 3 wasn't such an achievement anymore to do. :P Kind of dissappointing. *nod*

My best try before this tactic (when I was still attempting to use the shield on the right shaman and do the sequence manually). I lost one shaman and two shaman had the debuff drop off halfway-ish. Only on one did I manage to survive -and- keep the debuff stacking. 3/4 lived until the kill nonetheless but two of those did half the dps in that phase. So my four shammies, were basicly functioning as two. It was enough for my guild for the kill nonetheless. It was pretty frustrating to try and focus on multiple characters using shields all the while trying to keep the debuffs stacking. But with this one button tactic.. Pfffsh! A baby could do it. 8o