The idiomatic expression "to soak up the sunshine" means to bask in or enjoy the warmth and light provided by the sun. It is often used figuratively to describe someone who is spending time outdoors, absorbing as much of the sun's rays as possible, either through lying down on a beach or sitting in a park with their face turned towards the sun. The phrase can also be used metaphorically to refer to someone who is taking advantage of opportunities and experiences to learn, grow, or simply enjoy life.