I believe that if eyes are the windows to the soul, then the left eye in particular is the doorway. For this exercise you will need a partner, a living breathing human being. Find someone you are comfortable to practice with. Sit or stand opposite each other. Be as close as you can comfortably be.
Look into their left eye only, and have them look into your left eye. You want to hold their gaze for as long as possible. This can feel a little uncomfortable to begin with, but over time you will become more comfortable.
Take notice of what feelings come up. Do you feel scared or vulnerable? Do you feel open and available?
What do you notice about the other person? Are they holding your gaze? Are you picking up on their ‘energy’, their ‘vibe’? Do you oscillate between feeling very much in connect with them and then out of sync?
Practice this exercise often, familiarise yourself with what it feels like to be in true communion with another human being.