My DS is in reception class, this is his first week back at school after the Christmas Holidays. Twice this week I've had to have a word with his Teacher or TA as he has hit another child in his class. Both times it was the same child. On the second occasion, they did say he had been provoked. However it is still inappropriate behaviour and he was sent out of class. I have spoken to my DS about his behaviour being unacceptable and he completely understands this. He can reason it, he'll even say why he did it. He can explain why he must not do it, he fully understands the consequences of what will happen if he does it again. So why does he do it and what more can I do to stop him?!
It's not unusual sort of behaviour at this age. Lads his age have poor impulse control (not an excuse, just an explanation). I reckon that best thing you can do is back up the school in how they want to deal with it. It's happening on their time, they have to be the ones to deal with it.
He's just a baby. It's brilliant that he can talk about it with you. As long as you keep saying it's wrong, talking about it and there are consequences-eg he's sent out of class.-then it will stop. He's very young don't worry too much.
Role play what he shoul dhave done when he was provoked.