and what exactly is dotweaving ? im noob at shadow so please explain it
DoT Weaving is a style of play with Clarity of Power that alters your rotation when using the Insanity talent. This is an advanced rotation that yields slightly higher damage in single target situations. It is high risk, being that if you make a mistake you could lose damage over doing the normal Clarity of Power rotation.
Essentially, you will perform your regular Clarity of Power rotation until you reach 4 Shadow Orbs. At this point, you apply your Shadow Word: Pain and Vampiric Touch to the target. You will then use Mind Blast on cooldown, and you will use Devouring Plague two times per rotation cycle to get the maximum use out of Insanity. This allows your DoTs to tick fully before your next Mind Spike. Below, we present you with a cycle of this rotation (assuming you already have 3 Shadow Orbs saved up and will start out by getting your 4th).
Mind Blast (now 4 Shadow Orbs);
Mind Spike;
Shadow Word: Pain;
Vampiric Touch;
Mind Blast (now 5 Shadow Orbs);
Devouring Plague (now 2 Shadow Orbs):
Insanity for 2 global cooldowns;
Mind Blast (now 3 Shadow Orbs);
Devouring Plague (now 0 Shadow Orbs);
Insanity for 2 global cooldowns;
Mind Blast (now 1 Shadow Orb);
Mind Spike (your DoTs will have expired prior to this cast);
Continue using the regular Clarity of Power priority list until you reach 4 Shadow Orbs again.
A few more mentions are worth making regarding this playstyle.
DoT Weaving is a DPS increase in single target situations.
DoT Weaving works best with low Haste levels.
DoT Weaving becomes difficult to sustain when inside execute range because of Shadow Word: Death being available.
You can switch back to a regular Clarity of Power priority when in execute range.