“Paint yourself into a corner” means “to do something which puts you in a very difficult situation”. Example: They’ve painted themselves into a corner by promising to announce the results of their investigation.
Using a simple square hijab which means the length and the widths of the hijab are equal. Place the hijab on a flat surface and fold it across a corner meaning lift one corner and drag it across to the diagonally opposite corner of the hijab. Lift the hijab which is in triangular shape by holding the two ends across and place it over your head bringing both ends to the sides of your face. Tie a knot at the bottom or use a hijab pin to attach the two ends together.