I've been warming him up to it by decreasing his sensitivity around his face, holding a cloth over his eyes and around his muzzle, he's been very good with that. I have a feeling the fly mask will be scarier, with the sound of the velcro (I've seen ones with velcro, are there buckled ones?) and stuff. I'm just expecting him to freak and hurt himself as he tries to rub it off or something... I'd rather not be trampled either. He's not really a spooky horse, but he's always been a little timid about his face.
Do you have any suggestions as to how I should introduce him to the mask?