against any decent FLS during the incarn the key is to shift stuns on u, otherwise u wont be able to keep up the healing and either u or someone else will die. another important tihng is to get good tranq and top everyone, after incarn is over u shouldnt have problems with healing all u need to do is see when feral is running at u and shift his stun.
as soon as u see agony+siphonlife+corruption on urself - dispel it and there is no way u drop even to like 80% during the stun on u (while in bear ofc).
another usefull thing against fls is to play mana talent in 2nd pvp row. If u know that its gona be mana game u can try it but disadvantage of that is if u cant predict stuns and u have problems with keeping up ur teammates u will die with 100% mana anyway ;D