I was trying to poke from the front- furry side, until someone here pointed out the furry side's skin is tougher. You may do better (if you are not already doing it) trying to get the blood from the inside of the ear. I also use a small sock filled with (uncooked) rice which I warm up for 15 seconds in the microwave. Your microwave might be different, so test it out. The rice bags can feel cooler than they really are. After taking the bag out of the microwave, mush it around so you can feel how hot it really is. Be careful not to burn Stewie, sometimes I have to let the rice bag cool a little.
I also use a special treat. I buy bonito flakes from the asian food section of my grocery store- they are Japanese. Most cats love them, they are pure fish protein. I put a flat plate with them in front of Lolly, let her eat them for a bit, then prick her. It takes cats a while to eat the flakes, not like a quick treat that they scarf fight away, so it's a good distraction. She's so focussed on getting the rest of the bonito, that she sometimes dosen't know I pricked her. After I get the blood, I let her go to town on the rest of the Bonito flakes.