The ooooommmm is breathed into each area as you go around the small universe. You don't return each time to the dan tien. The two sounds alternate as you move from one energy center to the next. Don't be concerned if you get off track. When the exercise concludes, remember to just move through all the points back to the dan tien, in sequence of the direction you are orbiting, to the dan tien, to close.
Not sure what you mean with small and large universe... It either may refer to inside yourself and everything outside yourself, or just an extended orbit within self, extending down the legs and making a larger inner orbit. My understanding of the SFQ approach, is that all important areas connect to points on the small universe orbit, including areas that other methods might cover in a larger orbit. I find that "how" SFQ brings(visualizes) energy coming into the points on the small universe, unique, and very effective. Much more open to the larger universe and universal energy around us. I have learned longer inner orbit meditations, but they were much more closed in how energy was brought in , or moved through those orbits.
