Writing should never be used as a punishment. No matter what you think it teaches them, the thing they'll learn from it is to hate writing.

Perhaps the tip was not explanatory. The students actually voted it as useful and caring. This is not an assignment. It is to get them to open up. Two students were arguing loudly. They were called put in separate rooms and asked to write, why, how the will exercise control. Eventually they embraced.

Sorry I was not sufficiently communicative. In one instance two boys almost got into a fight on the soccer field. They were called by one teacher to calm down in separate rooms to write about who and why a team will win the world cup. The output was a gem in analytical football. One kept talking after the time out.They shook hands and walk together back.

You can force a grounding but not a writing assignment

Most answers are actually describing hostile school environments. I perhaps used the word punishment instead of cooling down. One student went int a tantrum she considered the gesture of quietly pulling her away from embarrasment as positive. She was asked to write about what she has on her Facebook page. Wrote more than required