This easy if you're left clicking the back icon, you can simply move the mouse away and release if you change your mind.
But what about when using a mouse with back and forward buttons on the side? Say you've pressed the mouse's own back button and are holding it down and then you change your mind and now you don't want to go back. How can you make it so that when you release the button the browser won't go back? Are you already committed or is there a way?