Positioning depends on the environment. If you are inside a wreck you take your buddies octo and position yourself above them, holding on to their bc/plate so they are towing you (yes, you should fin too). Once you are in the clear you link up and head for the surface facing each other holding your buddies bc or with arms linked. Cave divers are nuts so I'll step waaay back and let one of them tell you how they do it.