I noticed that too. It was interesting that Daryl knew what it was called. It also say something that the writers had T-Dog have one. Since without hair, despite being a black man, T-dog wouldn't have a durag because durag are for black men who wants to keep a certain hair style. So do the writers not know what a durag is for, and they just assumed every black men use them? Maybe I'm reading too much into this because after watching OITNB I'm paying way more attention to how writers write racism in all it's form.