I have used Dermaplast for years with Atty who would bite me otherwise.  Now I don't need to use it.

Dermaplast is a spray benzocaine that freezes or numbs the area where the needle goes in.  This has worked extremely well for us.

I also clicker train the response I want by having the horse target its neck to my hand.  Then I have it target its neck to the needle cap and train it put pressure on the cap, not me adding the pressure.

In zoos, they do 100 practice needle sticks for each real needle stick.  And if the vet doesn't get it right on that one stick, s/he has to stop and then the trainers do 100 more practice sticks.

Here's a video of my doing this with my Arab, Buzz:  https://www.youtube.com/watch?v=omXLWFnnOY4&t=41s.
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