If you build the IWT key into your normal dps key.
You'll either want a toggle to disable that mapped key (hotkey), or a toggle to disable/enable click to move.

I have two IWT keys for my melee team.
One is IWT built into their DPS keys.
I have a toggle which turns on or off the melee IWT.
The mapped key looks like this:

Hotkey 1 (and 2, and 3, for three IWT hotkeys).
On key down, run the mapped key which sends IWT keybind to all toons in my melee group.
On key up, send 1 (or 2, or 3) to all toons.

And then the toggle enables or disables the melee IWT (mapped key).
When it is disabled, spamming my 1, 2 or 3 (melee dps) keys does not IWT (as that key is disabled), but it will still send the 1, 2 or 3 to all toons.

Prior to this, I had CTM as a two step action.
Basically a toggle.
Press 1 enables it ( /console AutoInteract 1 ) and Press 2 disables it ( /console AutoInteract 0 ).

For pvp, you need the crazy chicken form of DPS.
As your opponent will move, and you will need to follow.
Testing on target dummies suggests no loss of DPS over standing stationary.

For pve, one press to get the team into melee.
And then stationary DPS is a lot easier on the eyes.

Also, if you are doing the chicken dance, during DPS.
Toons have a tendency to run off into the distance when combat ends.
Using Jamba for Strobe when combat ends, or being quick on the /follow hotkey alleviates this.
As does using IWT to kill a new target.