First of all, you need elective mode on. Then you set your 1 to be Companion, 2 to be Preparation, and your Right click to be Spike Trap. Then, you put the passive skill Vengeance on, which raises your Hatred to 150. All you need to do is cast companion and spike trap 5 times in 6 seconds, And they can be cast at the same time and there's no cooldown for either. You need to cast Preparation as you'll run out of discipline after 3 casts of companion, so essentially it boils down to:
1) Hold Right Click
2) Hit 1 1 2 1 1 1
Which should be 150 Hatred and 50 Discipline, and it should be able to be done within 6 seconds. I've also experimented with speeding it up by using Shadow Power and smoke screen, still not working. Anyone have any ideas how to get this achievement?