Assigning a keyboard to a specific app Sierra I have a Macbook Pro running Sierra with an external monitor and an Apple bluetooth keyboard. I would like a way to assign the bluetooth keyboard to a specific application no matter what application is in the foreground.  

For instance, if textedit is in the background on the second monitor, and chrome is in the foreground on the first monitor, I want to type only in textedit. 

Bonus points if there is a keyboard shortcut that disables this binding, and another to switch between apps bound to.
I don't think that it's possible to type into an application that is in the background. The keyboard will type into whichever application or document is frontmost. 
The keyboard shortcut cmd + tab allows you to cycle between the open applications in a left to right order. If you keep a lot of applications open simultaneously and the unidirectional cycling is unpractical, cmd + shift + tab allows to cycle backwards too.