The folks at Mozilla have recently released an Android launcher by the name of bg2droid. This is an experimental launcher by the company that is meant to simulate what it would be like to use Firefox OS. The good thing about this launcher is that it will not require the user to flash their phone or root it.
All you’d have to do is download the app and install it normally like you would any other launcher. Once you’ve got it setup, which should take a while, you’d be good to go and will be able to experience what it is like to run on Firefox OS. The launcher will also introduce some of the gesture-based abilities of Firefox OS, like swiping from the edge of the screen to switch between apps.
However as noted by Android Guys, it seems that with it being experimental, it isn’t exactly the most stable and might not be the best idea for a daily driver. However if you’d like to get an idea of what it might be like, head on over to Mozilla’s website for the details on how to download and install it onto your phone.