What joke did your last name make?

There used to be a guy named Zheng Xiaojun in our class, but later I was not much different from the two names behind him. My name is Zeng Xiaojun. Every time the teacher calls the roll, I will pronounce my name as Zheng Xiaojun. I didn't know who he was calling at first, but when it sounded like he was calling me, I was embarrassed to stand up.