Strawberry Marshmallow is a Japanese manga that depicts the daily lives of a group of elementary school students as they play, learn and grow together.

In the work, Sasazuka is one of the characters who is punished by his teacher for one of the following reasons:

1. Naughty and playful: As an elementary school student, Sasazuka may be quite mischievous and may sometimes do things that don't please his teacher, such as making noise, playing or pranks in class.

2. Learning problems: Sasazuka may have learning difficulties in certain subjects, such as math, English, and so on. This may cause him to be unable to keep up with the rest of his classmates and require special tutoring or correction from the teacher.

3. Rule-following: Schools usually have rules and disciplines, such as arriving at school on time, not arriving late and leaving early, etc. If Sasazuka does not follow these rules, he may not be able to keep up with the rest of the class. If Sasazuka does not follow these rules, then he may be penalized by the teacher.

4. Classroom discipline: In class, teachers usually ask students to be quiet and listen carefully. If Sasazuka talks or does something else in class, then he may be punished by the teacher.

Whatever the reason, free standing is a relatively common form of discipline, usually designed to make students realize their mistakes and help them make improvements in their behavior. However, in the context of modern education, this form of discipline has gradually been replaced or restricted as more emphasis is placed on protecting the dignity and rights of students.