When a behavior continues after low-key responses, or a student is openly defiant, move to a calm private conversation. Describe the behavior and its effect, restate the expectation, and listen, since there is sometimes a cause you did not know about. Keep your composure; matching a student’s heat almost always makes things worse.

Document what happened and what you discussed, factually and briefly, in case the situation continues. Know your escalation path before you need it: your department chair, the dean of students, and your institution’s student conduct process exist for behavior that does not resolve. You do not have to manage a genuinely disruptive student alone, and you should not try to.