If you're annoyed of your iPhone slipping out of your hands, here's an idea: replace the glass back with skateboard grip tape. Sure it might char up your hands but it'll never ever slip again! Jokes ...
It comes in colors. It sticks. Such is the Grip Tape line from RF Laserworks. They basically ad a dash of art to your favorite gadget while ensuring it never slips from your hand. They’re cheap too.