We establish energy cords with those we interact with. They get stronger the closer we become, or some, like those connecting us to family are inherently strong.
The energy cord explains why as you become close to someone, you often will think of them and see that they've texted you. By thinking of them, you're pulling on the cord and the other person feels this.
Not all cords are healthy. Ideally there is a symbiotic union so energy is being evenly exchanged. But sometimes we have people who drain us, or people who send us toxic energy through these cords. Be vigilant about how you feel when you think of, or interact with a person to know how their cord is affecting you. To manage this, we uncord the other person.
There are exceptions: sometimes we cannot uncord from someone no matter how hard we try because they haven't yet completed their karmic contract with us. This means there is more to learn in the relationship and once the lesson is completed we naturally uncord them.
However, many times people plug in cords just to drain our energy or to hurt us and in those cases we can and should absolutely uncord the person no matter how close to us they are. It often times feels like hooks being pulled out of us usually in our solar plexus chakra but they can also exist in other places depending on our relationship with that person. For instance, if we share a mental connection it is probably from the crown chakra; a sexual connection, probably from the sacral chakra; a romantic connection, probably from the heart chakra. To tell where it is, close your eyes and visualize the other person, then feel out where on your body the energy is coming from.
What happens after you uncord them? You'll often see that they reach out immediately. Other times they just... vanish even though they used to contact you a lot!
Just know that you deserve to have your energy for yourself and for those you choose to share with. For those who abuse this and try to take your energy it is unfair. They need to learn how to generate their own supply which everyone can and uncording them is a form of self-care.