What is it like to be a bat?

What is it like to be another person?

I'm not sure how to answer the even more fundamental question, "What is it like to be yourself?" What constitutes a valid answer? It's a vague question.

I don't believe that the phrase "what it's like" (in this philosophical sense) is coherent. When people like Nagel or Chalmers are asked to explain it, they liken it to other incoherent assertions.

It just means the experience of sensation. You're conscious of a purple object, the smell of brewed coffee, the feeling of a sharp pain, you have a resurfaced memory of a deceased relative, you visualize the beach, you dream of being unprepared for a test, You daydream while driving down a long road, you feel affection seeing a friend, you hear your internal dialog about the boss.

There's nothing incoherent here, they're just talking about subjective states of experience.

As I said, the phrase gets described in terms of other incoherent phrases ... it's entirely circular.