nochannel and target in macro?

So, I just respecced my lock affliction, and I was wondering about a castsequence macro I made:

/castsequence reset=target/combat [target=focustarget] Curse of Agony, Corruption, Drain Life, , , , , , , , ,


If I'm just button mashing, its going to continue to recast Drain Life right in the middle of channeling. I know that this works:

/cast [nochannel:Drain Life] Drain Life

but is there any way to incorporate that into castsequence macros?

/stopmacro [channel:Drain Life]
/castsequence reset=target/combat [target=focustarget] Curse of Agony, Corruption, Drain Life

This will only execute if you are NOT channeling Drain Life

I tested my original macro today in BRD. When Drain Life is in a castsequence, it will not cast a new Drain Life if I am already channeling one. This is pretty interesting... I wonder if its the same way with Mind Flay.....

I remember from playing a lock that activating drain life gives gcd, in that period I couldnt recast, but after the gcd (and in duration of drainlife) you should be able to cast?