Also keep the highest rank possible health pot ready, it's still our best heal. If you are in an area that allows it (next to a tree, rock, etc.) try to block line of sight of any hunters or ranged as much as you can for the duration of OB. This is good advice, the fear/big heal combo is a must, but also the part about positioning so you're facing things (especially burgs & guards in front of you). Not much, but it may give you a fighting chance.
I would suggest (assuming you are focused while being OBed) to face the freeps (mitigation is better when facing than from side or back), drop your fear (to avoid being inturepted while casting), drop your Hots that give +15% incoming healing and cast Fell Restoration right after.
