Put it immediately after the scuffle moment in your edit, then follow with a defiant reply like we do not care for the back-and-forth joke. For a stronger break-up sequence, swap that follow-up for hey let her go as the second intervention.
About this sound
This is an ultra-short spoken clip of a stern voice delivering a classroom rule: rule number nine, no fighting in my class. At under half a second it lands as a sharp, mock-serious warning. It feels funny and scolding at once, like an instant teacher voice cutting off trouble before it starts.