Depends on what content you want to take WAR into.
Dungeons - Just just bloodwhetting for everything. Trash pulls, bosses, tank busters. The damage reduction and self healing is broken in dungeons. Bloodwhetting is best used when you are around 30-40% HP remaining in trash pulls. If you want REALLY good mitigation put rampart on or vengeance...you'll heal to the MOON, and you'll mitigate way more damage.
Extremes - It's better to time your mitigations more effectively in extreme settings as the tank busters are more lethal if you don't mitigate. I wouldn't hit bloodwhetting non-stop, but it won't hurt anything. Thrill pre buster and Equal post buster. Combine with burst if it lines up for best results.
Savage - This is where busters, bleeds, autos really smack the tanks around. Tanks have to learn a mitigation rotation and what mitigation is needed for certain attacks through out the fight. It's also important to see what type of mitigation you can use that will be more then enough. Remember...if it didn't kill you....it was enough. Most savage Tank Busters this expansion were at or near the 2 min mark. So some of the busters you will be doing your burst...which coupled with bloodwhetting is perfect.
My advice....get used to your mitigations cooldowns as you will need to know when to use them so they are back the next time around. If you use them to late....you'll run the risk of it being on cooldown next Tank Buster.
Hitting your mitigations willy nilly leaves you open to not having them when you need them....trust your healers.
-Vengeance + Thrill is usually enough to get through most tank busters.
-Equilibrium following a tank buster is usually expected...but sometimes not necessary...results may vary.
-Bloodwhetting + Rampart is just as good as Vengeance.
-Sometimes tank busters will be followed up with a raid wide AoE. If you still have vengeance and thrill buffs....pop Shake it Off. This will buff Shake it Off considerably and give the party a hefty damage reduction buff/HoT. Vengeance and Thrill are "eaten" during this process. Remember...the buster is over so the damage isn't a threat anymore....you won't need vengeance or thrill. I would advise using Equal if your going to remove your buffs for shake.
-Nascent is an amazing skill. Don't underestimate it's usefulness. Put this on the OT during shared busters...this just heals both of you and takes pressure off the healers. Or put it on a squishy like SMN or MCH...it will heal them VERY quickly.
-Don't keep bloodwhetting on cooldown. This limits your options. Use it when you know you need it. The healing is ONLY 3/4 GCD's depending on how you time it. But Stem the Tide lasts for 20 sec...this means you absorb damage that is equal to a 400 potency heal. This is equal to a WHM assize level heal. That's maybe 1 savage level auto worth of damage that is absorbed until Stem falls off. Bloodwhetting on a tank buster is ridiculous damage reduction, and ok healing. I say ok healing because bloodwhetting in a single target situation with 3/4 GCD's is maybe a 1/3 of your HP restored.