Mine both love hair, too. Clyde gets downright grumpy if he wants to be a hairdresser and I interfere with him.
One thing I've discovered with Jade, who is VERY nippy, is that not reacting doesn't work as well as acting as if it's a game. I've learned to watch for the nip body language and often I can get out of the way in time, but not always. When she gets me, I laugh and say something like, "Ooh, Jade pinched Mommy good! One point for Jade!" This puzzles her (because she expects me to yell OW, like Hubby does

) and since I've been doing that, she doesn't chomp down hard at all. It HAS become a game and is no longer aggressive. She just nips to see if she can. That might not work for all Quakers, but it works on her.