Okay this is kind of just adding onto what Shorty6boy1 posted
Here
which was actually helpful, But i'm a clicker so..
If your one of those other people who click and not set key bindings, Heres how to do it.
I'ts actually very simple.
1. Make sure you have the "Lock Actionbars" option OFF.
2. When you click the wrong spell, or trinket/vanish at wrong time etc, DO NOT LET GO OF THE MOUSE BUTTON YET.
3. Simply drag it aside and move it back to the original spot and let go.
Instead of casting the spell (or using trinket/vanish/trap etc.) It thinks you were changing buttons around, So it will NOT be casted this way.
I use this on my twinks/alts in pvp alot. Saves a good amount of time cooldown
I'm not asking for rep but feel free to.
I'm simply adding onto what Shorty6boy1 posted