It's a method that tflofasho told me about. It's interesting to me. It's a method by a guy called Robert Bruce. This is what he says; First, you need to identify clearly in your mind events in the past that you can target. During altered state meditation, imagine one scenario at a time and relive it as clearly as you can. You can talk to your past self, offer advice, support, etc. You can give healing to your past self. During an obe, you would call up a scenario and shift there. This may happen automatically just by imagining the scenario. You can also make commands to help. Imagine the target scenario and say 'take me there' or similar. When doing this becomes a habit, you can then expect visits from your future self, as the habit of doing this will cause this to happen.