Have you tried "SpinPins"? They are amazing!

I have really long hair...on my head for the pervs out there! :D And the thing that always drove me nuts about my hair is I can't keep it in a ponytail. Didn't matter what kind of ponytail holder I was using, it wouldn't take long for it to slip down the length of my hair. When I was a teenager I wore my hair down practically all of the time but I don't really do that anymore because I want it up and out of the way. I usually braid my hair and then I use 2 spin pins in order to put it in a bun. They don't hurt my hair and they actually keep my hair up instead of it falling down every 5 minutes. I have no doubts if I tried to use regular bobby pins to pin my hair up into a bun, they'd slide out immediately.

Hope this helps! :)