If for some reason, you let your blood of the dragon fall off *cough* i'm looking at you neverreap *cough* then you have to revert back to an old rotation dubbed the rotation of shame.

Heavy Thrust > Impulse Drive > Disembowel > Chaos Thrust >Phlebotomise > True Thrust > Vorpal Thrust > Full Thrust > True Thrust > Vorpal Thrust > Full Thrust and then repeat beginning at Heavy Thrust.

Keep in mind whilst doing this you will be weaving cool downs between them.

You'll probably have to rely on this rotation until blood of the dragon is off cool down.

If you want a detailed version, please look out drg God dervy's in depth explanation. http://forum.square-enix.com/ffxiv/threads/238845-How-to-Dragoon-Per-Second-A-DPS-Paradigm