Make a castsequence macro and set it to the third button on your action bar. When you compile this script your going to want to name it notepad or calc.exe or something to avoid a ban. Warden checks open program names for common hack references.
The ` key ends the script even when your in the game and you don't want to spam the key anymore. If requested I can continue work on this and test it on a private server it might end up like my CA afk utility. Let me know how it works out for you.
Edit: I should have mentioned that this is an autoit script. Compile it before you use it.
Code:
#include <Process.au3>
#include <Misc.au3>
HotKeySet("{`}", "kill")
$dll = DllOpen("user32.dll")
AutoItSetOption("SendKeyDownDelay", 0)
While 1
Sleep ( 10 )
if _IsPressed("33", $dll) then call("t")
WEnd
Func t()
ControlSend("World of Warcraft", "", "", "{3}")
EndFunc
func kill()
DllClose($dll)
Exit
EndFunc