No one smeared anything, no one returned to his behavior. The boy knew very well why this had happened, and by the end of the lesson he was calm and hardworking. However, I probably wouldn't send a student to the corner myself. After teaching, the teacher came to me with the knowledge that she knew that it was not a very pedagogical procedure, but that it was the only way that affected him.
However, I probably wouldn't send a student to the corner myself.