I've only experienced violet wands if that counts. I particularly love the body connector that just lets you be the conductor. Very intimate and fun to cause tingling sensations just from your own touch.
If the ring starts to grab or pull, I've found a small amount of lube between the ring and your testicles help things rotate and stay in a better position.
Obviously if you find yourself in a situation where your body is fighting against it for more than a little bit, you should consider a...