We have an elderly diabetic cat and it's been a real chore testing his
blood sugar. It often takes 4-5 sticks to his ear to get a drop of
blood. I recenly stumbled on a technique that works every time.

While my wife holds him still, I insert my thumb in his ear such that
the ear is backed by the thumbnail. I then press the lancet pen
against the ear so the ear is held solidly in place against the nail.
I've gotten blood first time every time.