不穿校服

Meaning

Refers to "bringing smiles through dueling" (決帯笑). From Yu-Gi-Oh ARC-V protagonist Yuya's catchphrase. Good intention, but in reality the winner smiles while the opponent might not. This forceful way of making opponents smile is mocked as "beating opponents into smiling through dueling." Also means "using dueling to make yourself happy and opponents suffer."