"Read it To me" x "Read it For me": Qual é o certo?

Hi, again! As a teacher, I always ask my students to read some things aloud, and I sometimes say "can you read it to me?" and sometimes "can you read it for me?". I have this in mind that when you do sth to sb is that you do as a favor or because the person is asking to. When it's do sth for sb is that you do it instead of the person, in their behalf. Is that ok? So, as a teacher, when the st is to read a text or some exercises, what should I say: "can you read it to me?" or "can you read it for me?". I'm confused on that one and I need your suggestions. Many thanks!!!