telling off- how much?

[plus3]

my DS is in Yr2 and was told off by his teacher for strangling one of his class mates. she has dealt with it, removing him from playtime and told him that it was dangerous etc.

Ds is sorry, but said the other boy was laughing. He doesn't seem to really get how dangerous his action are.

I have reiterated how awful this was, but he just seems to have stopped listening to me.

Any suggestions? The teacher is suggesting that we just absolutely praise the good stuff, which I understand,but feel I am failing to get through to him ref.the mean behaviour to his classmates

Anyone?

I'd say impossible to say without knowing your DS and exactly what you've said and what it was all about. What is yr2? 6? And you are sure he hasn't taken it in? the seriousness?

Perhaps try sitting "casually" with him and talking about what he was feeling. Depends on what he says - angry? just playing?
You could help understand his emotions, if required.
Then you have to explain in simple terms what would/could happen. If he still seems oblivious get more explicit. Tell him the other boy could have died. Ask him how he would feel if his mum/dad/brother/sister (someone) was dead and never to come again. Explain how upset you would be if it had happened to him.

Just a suggestion