Duck's Ass Hairline
It’s all stringy and thin. I do straighten it daily, but I use volume shampoo and deep moisture conditioner, and heat protection spray, prior to heat tools. What could be affecting the thin stringy side at the back, as it’s really annoying? It never lays flat and always flicks out, etc.
My first suggestion is to have a stylist check the thin and stringy side for signs of styling damage and breakage. This will tell you if a change in your styling habits will resolve any of your issues. If there is no sign that the condition is caused by damage to the hair, then, you should assume that it is a natural variance in your scalp and act accordingly.
My best advice would be to consider an alteration in your current hairstyle in order to compensate for the thinner side. This could include shortening the length at the back, or using thinning shears to remove some of the thickness of the dominant side. This would bring the look into balance and help to maximize the appearance of the hair.
Remember: with thin hair, extremes are often your enemy. Too short, and the thin hair allows the scalp to be too visible, while if the hair is too long the result is a stringy looking mop. Consult with your stylist on the best way to balance your length versus the density of the hair in back.
©Hairfinder.com
See also:
Hair density
Hair wave patterns
How to use thinning shears