Great post beau. Agree with all but the very last line - just because it's an ambiguous term that grates on me - may be right but doesn't help work out what to do about it.
Missed the bit about biting...
As for the biting I do correct him all the time and nothing seems to phase him, he just got me after a lesson today right in my back.
If you have to punish more than a few times for the same behaviour, you're not being effective & may actually be making the behaviour worse. Eg. the horse sees it as a game that you're joining in on - you get me, I'll get you - probably likely outcome with this horse by the sounds. So there are a few things you need to keep in mind when punishing...
Punishment, unless there is no motivation for the 'bad' behaviour(eg. it's happened 'out of the blue', experiment for the horse...), does not tend to end a behaviour instantly, only(if effective) weaken it. Therefore it's best to also use other methods of changing the behaviour, such as positively reinforcing the horse for alternate 'good' behaviour, such as keeping his nose in & down.
Any punishment or reinforcement needs to happen *at the time of* the behaviour you want to influence, or *at worst*, *within* 2 seconds of the behaviour. If it comes after, the horse doesn't associate the cause to the effect very well.
For punishment to be effective, it needs to be strong enough & unpleasant enough for the horse to want to avoid it. Especially when talking a playful horse - & they play rough - this may be quite severe. One reason why I think it's best to avoid punishment where possible & use it judiciously. I personally tend to save strong physical punishment for situations where my safety is the concern.
So... I'd first be focussing on teaching the horse 'good manners', including keeping his mouth to himself. The more opportunity he gets at being reinforced/rewarded for 'Good' behaviour, the better he'll get & more he'll want to try these things with you rather than the 'Bad'.
As beau has said, especially until his 'Good' behaviour is well established, always try to be very aware & in control of what's going on - eg. if you do need to turn your back or such, make sure he's on lead or on the other side of a fence, so he doesn't get the opportunity to get you when you're not prepared.
As for punishment, I would try to remain separate - eg. use a method that is not seen as me going after the horse, set it up that he punishes himself. Eg. if there is a common time/spot he is likely to bite, if there just happens to be a wire brush or some such there, that *he* spikes *himself* on, that's usually effective. If you're going to have to actually get after him for it - & lets face it, things don't always go according to plan that you can set it up perfectly - I'd be watching his bodylanguage & get after him when he *starts* to think about biting, and do it hard & fast, so he doesn't just think of it as a game, but wants to avoid your response.
**And do it in such a way as to stay safe - eg. if he's not on lead so has to face you, or you don't have a big stick/whip to stay at a safe distance, probably safer not to do it at all.
Hope that helps & it's not just as clear as mud!