Pretty much, have an IWT keybind which you spam.
And your DPS keys.

If you are using IS Boxer, you can go with "Steps".
Where press 1 is IWT.
And press 2 is your DPS key.
Then spam twice as quickly, or use up/down states.

If you integrate the keys like this (or use the penny glued across two keys method).
With IWT keybound to one key, and your DPS macro on the other...
You'd want a toggle to enable/disable IWT.
Since IWT is a keybind, we cannot really do this.
But IWT needs CTM (click to move) to be on, to have it move toons.
And we can macro CTM on and off.
/console AutoInteract 0 (off) and /console AutoInteract 1 (on).