I belong to a knitting/crochet group that make projects for a local charity.  We meet every couple of weeks and I get to photograph each item that is being donated.  For this photo, I had one of our members turn her back towards me so that I could photograph the knitted scrunchie that she had made.

"Turn your back" is a fun prompt because it can be interpreted literally or creatively.  A person walking away, someone looking over their shoulder or a person with their back to you.  Or it could be a photo of someone deliberately turning their back on something such as a piece of cake, a pile of laundry or even your camera!