Hold the rag lengthwise. Fold it in half (the long sides toward each other) and over the end of your hair. It's still lengthwise so you have two long ends. Now, roll your hair up close to your head and tie the ends.
With heat of course. Curling irons and straighting irons basically burn your hair in that position. It does do what you ask it, but it damages your hair.
The Heat makes your hair contract, basically your hair shrinks in the heat in areas pulling the rest of your hair causing it to curl, same thing happens with plastic. People also want it to curl...
It's recommended that you spray the hair after you have achieved the look you want to hold in place.You may use other products designed to be used prior to curling to assist, but hair spray itself...