By nature we identify each other on a soul level. So basically you are feeling someone’s energy around you and using your clairsentience to feel or sense someone’s presence. In mediumship we use clairsentience when we “sense” a presence around someone’s aura. Then our clairvoyance, which means “clear seeing” kicks in andSome real life examples here would be feeling someone behind you and knowing who it was without looking. Then you turn around and you receive validation, that it was the person you saw in your mind. Every living thing has an energetic presence. You can feel a person’s energetic signature before they may even be physically present. Maybe you felt someone in particular was going to call you on the phone and then the phone rang.
We have to remember that energy presence is a two way street. We also can send our energy to others without even realizing it. Perhaps you were thinking of someone and then they contact you and say “I was just thinking about you.” This would be because they felt your presence and your communication to them without even saying anything.