It can be really helpful to establish a routine with testing. Pick one spot that you want your "testing spot" to be (I like the kitchen counter because it's got good light and it's at a good height....it also already blocked 2 escape routes due to the wall and the backsplash) It can be anywhere though...a rug on the floor, a table, a particular spot on the couch...wherever is good for you. Take him there as many times a day as you can and just give his ears a quick rub and then he gets a yummy (low carb) treat. A small piece of baked chicken was China's favorite
Most cats aren't objecting so much with the poking..it's the fooling with their ears they don't like, but once they're desensitized to it and learn to associate a certain place with the treats, they usually start to come when they're called! Or even when they hear us opening the test kit!
You also have to remember...you're not poking him to hurt him...you're testing him to keep him safe and understand what's going on inside his body. There's just nothing better than truly understanding what's going on inside your kitty's body and with this disease, the more knowledge you have, the more power you have against it. The edges of the ears have very few pain receptors, so it really doesn't hurt them. Also, if you're nervous and tense, it's going to make your kitty nervous and tense too. As silly as it might seem, try singing! It forces you to use a different part of your brain!
It's also important to make sure his ear is warm. A small sock filled with a little rice and microwaved or a small pill bottle filled with warm water or a washrag soaked with warm water and put into a zip-lock bag (check temp against your wrist like you would a baby bottle) works well