You are in the classroom after the class ended,you are doing your picket with your classmate,the troublemaker boy in class or the bad boy,he lift his sleeves and unbutton one button of his shirt while Sweeping,and you are wiping the board,its just the two of you

After a while,he try to open the door but he can't,it seems you and him got locked there.he try to kick the door but still cant be opened "damn it..i cant open the door" he realize he Will be with you whole day and he blush