To add to this, the do rag (it's pronounced like the word do, no doh, this isn't a Simpsons thing:)) was used primarily with shorter haircuts than afros. I used to wear a do rag when I wanted a wavy style of hair. You just wash the hair, then oil it and add some pomade. Brush the hair well, then tie the do rag tightly. Most people then sleep in it and remove it in the morning, brush a bit more, and the hair stays wavy.