Advice on tips for dealing with blatant defiance in a 4 year old.

[user1464795209]

I really need some advice on how to deal with my son when he's being defiant . He will refuse to do stuff and then scream like he's being tortured if I say he can't have something .. Like this morning when I told him and calmly explained why he couldn't have a second chocolate mini roll . He just said 'I'm gonna open it any way so there ' then I took it off him and he spent about 10 minutes screaming like he was being tortured. What do I do in this ( all too recurrent ) episodes ?

Thanks

[user1464795209]

Also says horrible things during the screaming like

I hate this house
I hate you

Etc etc... This happens a lot