From EJ (
http://elitistjerks.com/f77/t37074-s..._specs_glyphs/)
Mearis writes:
The traditional opening sequence is something like Vampiric Touch, Devouring Plague, Mindblast, Shadow Word: Death, Shadow Word Pain - since at this point all the debuffs should be stacked on the boss.
On use + crit trinkets should be used prior to casting Shadow Word Pain as well.
After you have gotten all your dots on the boss, play as follows:
1 Refresh VT as priority number 1
2 Refresh Devouring Plague as priority number 2
3 Mindblast if 1 and 2 are done
4 Mindflay is 1, 2 are done and Mindblast is on cool-down
5 Shadow Word Death iff you need to refresh a dot in ~2 seconds and mindblast is on cooldown. Shadow Word Death is almost never worth using except when opening, since it causes two shadow vulnerabilities when building up your stack.