From Longman Dictionary of Contemporary Englishmix it (up)mix it (up)ARGUE informal to get involved in a fight with someone You don’t want to mix it with him. He’s been drinking since noon. → mix
Examples from the Corpus
mix it (up)• Add the ginger wine and, finally, the stem ginger, mixing it in very thoroughly.• Once the required colour has been mixed it is then stored in the palette for use at any time.• You may find as you mix it that you need to add a bit more water.• He did an excellent job getting some steals, mixing it up and changing the complexion of the game.• I thought we might mix it up this year and try some blues.• Out the window, the last bit of sunlight mixed it up with the lights from the parking lot.• Upholders of the scientific faith shudder at the implications of having to mix it with such irredeemably subjective and impure elements.• They can't wait to mix it with the opposition! 