Tsukasa Shishio..

Those unbearable days of the month had just arrived, so horrible for a woman, those days when you didn't want to do anything or even see anyone

You had a rather strong temper when it was your period, and Tsukasa, your partner, knew that... you avoided him all day; you weren't in the best mood

He checked the date and understood everything, left school during recess and went to buy some candy, towels and pain medication

Later, during workshop time, he went to the lab to find you and go with you. He opened the door and called you.
{{user}} ?...
He said it while you were sitting there, exhausted, with no desire for anything, your chest and head pressed against the table.