I would hold him, calm him, rub him down with it, maybe rub him down with other smaller things like towels, get him used to it's sound and feel, put it on him securely and turn him out. It'll be good for him... his first 'sacking out'.
Never let him get away with turning his butt to you to intimidate you. I'd have a line on him and if he tries that he gets smacked. With him under control and you in a safe direction, of course.
Good luck with those bunnies.... I've never had luck saving them. I've rescued them too late when they already had an injury and they've all died. I have lots of bunnies around here in the spring, my dog got a couple she killed before I could save them, it's the cats that just torture and toy with the poor things.
Because he's young and unbroke, and I don't know how much experience you have, I want to be careful to say you shouldn't do this if there is a chance he could get away from you before you get the blanket secured... I would desensitize him to it while closed in his stall if possible and with you holding him really securely. With it just laying on him, rub and pat him and get him used to how the straps will feel, but you can pull it back off him if you think he's gonna go ape, and start over slower. Once you decide to start fastening straps, you're committed and you should work quickly. Do one of the chest straps, belly straps fairly tight around him so he can't get a foot through them (they should be crossed if there are two belly straps) and do the stretchy back leg straps last. Then he's secure and you can turn him out in a secure paddock for him to run, roll, and try to buck it off if he will. He'll get used to it once he knows he can't get rid of it. If he gets away from you before it's completely fastened, it is much worse, and he might ruin it before he stops.
How well he takes to this will be a good indication of how easy he is going to be when it's time for him to be backed...