maybe you might be putting it on too slowly. i find with putting my headcollar on my pony hard because i'm too slow and he starts throwing his head back.  it might be the fact that your taking a while to put it over his eyes and the bridles blocking your horse's vision.

Try rewarding him when it's on....especially if you manage to get it on with minimal (for him) fuss.

I've been having a similar problem with the horse i've got on loan. As soon as i grab his head to put the bridle on he starts to toss it up and down and resuses the bit. It's 'fine' with me, but the women i share him with is slightly novice-y and could not get it on on her own, so we started to reward him. As soon as the bits in his mouth and the head piece is over his ears he gets a polo before we start messing about doing it up etc...and with in 3 days he's alot better already (i think my friend even managed to get the bridle on on her own today which is a first)

maybe the pony is just being rude as he doesnt want to be rode, if he has got away with it in the past.. he may just try still do it! i would suggest just practising putting his bridle on and not riding him so he doesnt think hes going to get worked all the time.. x