There are generally three reasons for the flattening of the back of the brain. First, it's natural. When the mother is in labor, the fetal skull will be squeezed. At this time, the fetal skull is soft, and it is easy to form a flat head after being squeezed.
The second reason is acquired. Many people think that a flat head will make children sleep flat, but it will not affect their health. They just changed the shape of the back of the head. The third reason is caused by disease. There is a disease called "posterior skull flattening". Due to lack of oxygen in the brain and insufficient mental exercise, the head is flat.
Boys with a flat head can choose to hollow out the hair at the back, leaving only the hair on the top of the head, so they don't have to worry about the hair protruding from the flat head. It's also cool to comb it casually. You can comb a round pot cover directly, or you can comb your hair.
Or simply highlight the bright hair color in the back of the head, the color difference will cause the illusion, and people can't see the flat head. You can also shave off the shape behind your head. With the cover of the pattern, the flat head is not so obvious.