Characters
That’s the thing about friends, they will always hold your hair back when you’re sick.
— Carrie · Sex and the City

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker defines friendship through a small, unglamorous act of care: holding someone's hair back when they are sick. The practical example gives loyalty a physical form. Its warmth comes from treating help at an uncomfortable moment as something friends can be counted on to offer.
Context reviewed