Float Lock

Don't ever look for an orientation button.
No need to open the tiles drawer.
Float Lock will help you do it easily and from anywhere.

It’s happened to all of us. You’re lying in bed and have screen auto-rotation on, and as soon as you open an up on your home screen, the screen turns sideways. Yes, we know we can turn off the auto-rotation in the settings, or change the position of the phone until the text is upright once more, but we’re a lazy people, in a lazy generation aided by technology, and if there’s an app for something, then problem fixed. Samantha, XDA-Developers.

Currently Float Lock is completely free and doesn't have any ads.