This will cast a different spell in the sequence each time the button is pressed. It will reset when you leave combat or change targets. This has UA last, and allows you to cast 3 of your 4 dots while on the move, and regain health from SL at an early stage. This macro will cast Amplify Curse if you hold down alt.
#showtooltip
/cast [modifier:alt] Amplify Curse
/stopcasting [modifier:alt]
/castsequence reset=Target/Combat Corruption, Siphon Life, Curse of Agony, Unstable Affliction