You look around with the Oculus Rift, but you still need the mouse (or another controller) in order to sit comfortably while playing and spin all the way around. This left me in the position of having two ways to turn my body. Having two ways to turn is fine but if one of them is your head, you will drift out of a comfortable position over time. How I noticed this was that after less than a minute my head would be twisted uncomfortably left or right and I would have to center my view by looking forward while using the mouse to counter-spin my body so that my game view would continue looking where I wanted to go. After a little thought about this I came up with the idea of a "Definite Forward."
A Definite Forward basically means that whatever "forward" means to your avatar should not change while you look around. If you think of Mechwarrior, this would be like torso-twisting a mech. If you press forward you'll continue in the direction that the legs are facing rather than move in the direction the torso is facing. In this way a player is free to sit in their chair and look in any direction without ever having to break immersion to compensate for their head orientation with other controls.
You know who did a good job with this idea? The EVE guys with Valkirie
Their Definite Forward is their cockpit. From your head's point of view the cockpit is stationary and you look around within it, never having to adjust for any way that you control your ship. The same could be said of the interior of a car (hint, hint).
I used this premise in SnowDrift (https://developer.oculusvr.com/forums/viewtopic.php?f=51&t=3665&sid=ee7c4e95a1663a7df30765afb945b689) too by deciding that the player's skis would always point "forward."
There is one challenge created by this method though. If you're not moving your head to change your player's orientation, why do it at all? If you don't do it you're missing so much of the VR experience. This challenge can easily be overcome with game mechanics though. Watch the Valkirie video again and pay close attention to all the game mechanics that cause the player to move. There are lots of them. I didn't do this part very will in SnowDrift, but I've got some things to try before release.
Having a Definite Forward in your VR game can help reduce moments that cause the player to break immersion. It works best when paired with other mechanics that entice the player to explore the features of VR.