get up in someone's face

get up in someone's face (third-person singular simple present gets up in someone's face, present participle getting up in someone's face, simple past got up in someone's face, past participle gotten up in someone's face)

1. (slang, African American Vernacular) To dramatically confront or initiate an argument with someone.

   After he called me that, I couldn't help myself from getting up in his face.