How would i make two things center upon eachother?

i have a vr headset, and i'm trying to make a smooth locomotion system for vr. Currently, how it works, is that your current camera or 0 0 0 in vrspace is always at a small ball, that rolls around. this makes an easy smooth locomotion, but it's stuck in one place, the center of your room. how could i make it center underneath the player, yet have the player move with or center with it? If i just move the ball under the player, the new ball location becomes the center again, the player relocates away from it, and this loops and flings you out into space.