You think you’re a big man for mocking me?
One may use the phrase “You think you’re a big man for mocking me?” to ask if another thinks that they are a "big man" because they are teasing (“mocking”) you. This phrase may be used as an exclamation or/and to ask another’s intent.
Once the student had stopped teasing her, the teacher asked the student, ”You think you’re a big man for mocking me?”