Living in the world means a life full of relationships, with people but also with the objects of the world and the thoughts in the mind. Living in the world means a life full of changes, which occur because of the appearance of time, space and causation. Living in the world means a life full of opportunities and choices, which means dealing with wishes, wants and desires.
Tripurashakti‘Living in the world, but at the same time not being of the world’ means playing with and mastering these things, all at the same time, plus gradually growing in non-attachment (vairagya) towards the world and all that it includes. When non-attachment has expanded so much that you are able to set aside everything (for a while), you’ll rest in your True Nature. This means that Yoga (Union) has happened.