I have finally, at least to my own satisfaction, been able to describe what shamanic initiation DOES, and perhaps even why Bataille thought that Nietzsche's emotional breakdown with the Turin horse was in some sense a breakthrough, odd as it may seem. (This relates to a certain logic that we feel we must transcend ourselves because of shame and guilt, but we can RETURN TO ourselves through no longer trying to take stiff measures to distance our emotions from life's violence).
Humans as such feel guilty and ashamed of what is possibly within us, not just in the ability to act out violently, but also in terms of our potential to succumb to violence. So we hide ourselves from ourselves in small containers of the mind. And we accept bondage so that our emotions may not longer range to the limits of our being, where we would risk finding out what lurks there. Externally imposed servitude produces is desired because it produces safe sensations (--which is what is on offer from monotheistic religions). But shamanism cracks the mental shell to open you up to all of what life is.