/castsequence reset=target Serpent Sting,null /castsequence reset=0.3 2,2,2,Black Arrow /castsequence reset=0.3 2,2,Kill Shot /castsequence reset=0.3 2,Glaive Toss /castsequence [mod]reset=0.3 cobra shot; explosive shot
Here is how its used.
As you hold down, or mash, the button you have this on it will first apply Serpent Sting. It will work its way thru the macro applying Black Arrow and Explosive shot. It will fire Explosive Shot with Lock and Load procs too.
If you need focus, or serpent sting is about to fall off, holding down any mod button (ctrl, alt shift) will cast Cobra Shot, which give back focus and refreshes some time to your Serpent Sting.
Now you need to weave in Arcane Shot too, What i do is put that on another button, i use that when when i am about to cap focus, when i have time left on Serpent Sting and every other ability is on cooldown. i can press that once or twice to dump some focus.
To play it safe i always keep serpent sting on a separate button too.
I know its not a all in one, It only takes 3 buttons to execute it, but offers a superior amount of control that a all in one cannot. It is also small, under 255, something if you ever seen any of ret/prot, shadow priest, or other macros, that i am very proud of being able to accomplish. Bigger is not always better.
Hope you give it a try and practice with it. Its very easy to use.