To light each other up in English would be to say "to illuminate each other." This phrase comes from the concept of providing light for someone or something, often figuratively to provide understanding or clarity. For example, you could say "We need to illuminate each other's ideas in order to find a solution to this problem." In Chinese, this could be translated as "我们需要照亮彼此的想法,才能找到解决问题的方法。"