I posted this elsewhere when someone asked

Assuming you're starting with all CDs
Raging strikes - Bio 2 - Miasma - Bio - Fester (make sure Bio is applied first, it takes a second) Thunder - Contagion - Ruin - Ruin - Fester (RS should still be up for this 2nd fester) - Ruin until it's time to reapply DoTs. Also dots cannot clip if they have RS up so don't bother casting bio2 until it's 1-2 seconds left, etc. This is your boss rotation, fit in Rouse, Spur and Enkindle whereever since they're off GCD and just need animation time. Shadow Flare in place of Ruins when needed. you can swiftcast it but I prefer keeping the swift ready for someone else fucking up and dying.

For normal enemies Shiftcast shadow flare on them - Bio2 - Miasma (Use contagion when it's about halfway cast) - Bio (contagion should hit right after bio applies) - Bane - Tab Thunder on everything if you want, fester the rest of your Aether since the fight will probably take a minute depending on the other dps. Spur and Rouse Garuda whenever, you can enkindle if it's off CD.