When one is listening to music of a Grime origin, one may wish to show one's appreciation for such music by moulding one's face into such an expression. This expression is comprised of a look of disgust often accompanied with rocking one's body to a beat and moving one's hands in an appreciative movement, as well as grunts of 'uh'. The more disgusted the look on one's face is the more appreciative of the music one is.
Person 1: Check out Victoria's grime face, she is loving that sick bass.
Person 2: She's getting grimy.
Person 1: She sure is.