For dark skin, how do people laugh at themselves humorously when they talk about themselves?

Black is a healthy color. No umbrella in summer, and the sun absorbs heat in winter. Of course, this is just a joke. How to tell others that you are black, I have the most say, because my skin is generally black, and, I don't know whether it is God's will or what, my friends around me seem to be whiter than me. For example, I have a sister whose skin is very white, and then she grew up, how can others tell us apart? The white one is my sister and the black one is my sister. Every time relatives and friends ask, alas, why is this girl so dark? They were all born to the same mother. By this time, I will use a joking tone. I said that my mother drank milk when she was pregnant with her sister and black-bone chicken soup when she was pregnant with me. I skipped the question in this cheerful tone.