I made a click sequence for my affliction lock to line up with the cast priority I found on EJ:
Shadow Bolt -> Haunt -> Unstable Affliction -> Corruption -> Curse of Agony->Shadow Bolt

The first Shadow bolt is a starter: /castsequence reset=target/combat sb, null
Corruption is similar since it refreshes with haunt.
I have drain soul on a separate button since I only use it on boss fights.