Ive seen plenty of guides on how to prevent the launcher/sidebar from ever auto-hiding, but how would I prevent it from ever showing except when I press the left cmd/win key?
You can try CCSM to autohide the launcher.
To do that, install CCSM by clicking the link. After installing it, open CCSM and go to 'Ubuntu Unity Plugin' under Desktop.
Choose 'Autohide' option in the dropdown list next to 'Hide Launcher'. Now, the launcher will show if you move your cursor to the left side or you press the Meta key.
So, in order to prevent the launcher from appearing when you move your cursor to the left side, go to 'Reveal mode' in the same option page and unselect all the selected corners. If your dialog box looks like the picture below, your launcher won't appear even if you move your mouse to the left side.
You can try using dconf-tools .
Enter these commands in a terminal:
Alternatively, you can use the GUI of dconf-tools.
Go to com -> canonical -> unity-2d -> launcher and change
Note: For Unity-2d, editing the reveal mode for launcher is currently not available and hence, you can't prevent it from showing when you move your cursor to the left side.
If you install Ubuntu Tweak you can customize some Unity settings, It is possible to set it to "auto hide" where it is always hidden until you mouse to the left even if there is no window there. That is all I can think of but if your problem is it popping up when not wanted you could always try changing the timeout where you would have to leave your mouse against the left edge of the screen for a desired amount of time until the launcher will reveal it's self, this can also be changed in Ubuntu tweak. For the Ubuntu tweak .deb file you can download it at the link below. http://ubuntu-tweak.com/ Hope this helps, Ross