Kim- Hang in there! You're going to get this!
I freehand poke too. It sounds like you've already been doing some reading about all of this, which is great. Have you already seen the picture that shows the "sweet spot" for where to poke? Their ears do bleed better as time goes on, so just remember that every poke - even if it doesn't result in a test - is still working towards making this better.
The larger lancets will really help. And when you say his ears are warm, are you warming them with something? Or they just feel warm to the touch? Many of us put some uncooked rice in a sock, heat in the microwave, and then use that to warm their ears. I've found that to be super helpful.
After you poke, you may need to massage the ear a little more to get the blood to actually come out. This is especially true if the cat is a bit dehydrated (a common state in newer diabetics since they are drinking a lot, but peeing it all out). Starts at the base of the ear, and rub upward toward the poke site.
And yes, Sam was feral when I got him. This whole process has gone a long way towards taming him, but when we first started, it was comical watching me run around the house trying to coax him out for testing. And then trying to figure out how to get the test without him feeling like I was holding him down, because if he felt confined he would go into attack mode. I never thought we were going to get it figured out, but now he's super sweet about it (most of the time).
