The man asked me what my major was. How to reply humorously

Do you care so much about my major that you like me?

You can reply like this. When we encounter this kind of problem, we usually subconsciously give him a clear answer. For example, we are majoring in civil engineering, maybe we can answer that he is majoring in civil engineering. If you don't want him to know what your major is, then you can use this answer.