"Don't you dare!" is an expression that communicates a warning to someone. It's a way of saying "If you do that I will be extremely angry!" Say it in situations like these:

• Your children try to disobey you.
• You're in an angry argument with someone who's trying to blame you for something that's not your fault.

You can also include the action that you don't want someone to do:

Don't you dare talk to me like that!

Don't you dare leave without cleaning up this mess, young man.

"Don't you dare" is usually said very angrily or strictly, so be careful about when you use "Don't you dare!" However, there are some situations where people use it without any sense of anger. In TV commercials, you might hear something like:

Don't you dare miss this sale!