The same thing was happening to me. Don't reef on the thread when you start out. Do a half dozen or so wraps with just enough tension to hold the hair in place. Then start tensioning the thread more as you go. This way, the thread that is already laid down takes the tension and not the hair. This has stopped mine from flaring.
Also, if you pinch the hair and do a 'loop through' between your thumb and forefinger three or four times before you let go of the hair (again, don't tension the thread any more than necessary), it won't spin around the hook shank. I keep my fingers on the hair until I'm done the wrap but that's just me.
HTH