Not sarcastic. . Use it playfully. . It is "taking a liberty", doing something that is not proper. Calling someone a name. Saying something inappropriate. Most often with teh purpose of making fun of someone. . Don't give me any of your cheek. = don't be cheeky. = almost= mind your manners. . Tone alone tells you whether the person is serious. Child steals a muffin. Ohh, you cheeky blighter. Come here. I'll teach you a lesson. Most often with children.

Often, it means "not showing proper respect".

John is right : cheeky means not showing proper respect. But, as @Nanren888 says, the concept of 'cheekiness' has a playful aspect. It's often used to refer to children who disobey or make impertinent remarks - but in an endearing way.

No, it doesn't mean sarcastic. Sarcasm is very different.

its like sarcastic hes very cheeky with him hes very sarcastic with him