Generally in heroics etc the thrash dies so fast.. if there is a pull that is more than 2mobbs pref 4. Slap swp on your target and MS the target that has SWP.
If there are only 2 targets, that die fast.. doenst really matter. The most effective option probably is just MB, flay the main target and swp/dp + mb mf the secondary target.
1) If you are showering, mind sear.
2) When shopping for used automobiles, mind sear.
3) If there are more than 4 Ritz crackers left in the package DO NOT MIND SEAR.
These three simple rules will carry you to shadowy glory.