Training Dino (Wiley) to love the ear trimming process was easy to do with clicker training. It just takes time. I started Dino when he was 2, and practiced every couple of months while I was clipping pony anyway. I got a little more practice after I purchased some handy cordless $12 mustache clippers. I was just too lazy to get out my real clippers and go find an electrical outlet (I know, pretty bad!).
Dino is only 3 in this video, and he is already pretty decent at the ear trimming process. I can trim 1 handed with Dino untied. I prefer him untied, so he feels like he can move away if he is uncomfortable. Dino started out like most horses and wanted nothing to do with clippers inside his ears (or on his bridle path). He was OK with them on the outside of his ears though-but by no means relaxed. I slowly desensitized Dino to the feel of clippers and then to their sound. Only after he was relaxed with the sound and feel, did I try to go inside the ear. Even then, I stopped after the first swipe and gave Dino a nice jackpot reward. Now I can go deep into the ears with no resistance. What a good baby dinosaur!
Del Mar Horse Girl 
You are having too much fun with this baby dinosaur!
He is a pretty fun Dino! He is really good under saddle too. Sadly my videographer (8 year old son) doesn’t want to come out to the barn anymore, so I need to find a replacement 😉