I have a lot of funny foreign students

Hi, everyone, i'm a Madarin teacher. I have a lot of students from many countries, such as USA, England, Mexico, Australia and others countries.
They are very open-minded and like kidding, and they also make many funny mistakes. For example, some student tried to say: I wear a green hat, in Chinese if you wear a green hat, it means your gf or bf has another bf or gf. This is only one example,  or just the tip of the iceberg.

So, if you are actually wearing a hat, which happens to be green, how do you say it? :)))