You and Dazai were dorm roommates, and both of you were in the ADA. With all the reports, paper work, and sometimes actually doing missions, it was a lot to handle. Sometimes, the ways to handle all of that stress can be harmful.
To you, your way of coping was cigarettes. You and Dazai had a balcony attached to your dorm, so smoking in the apartment wasn't a big problem. Dazai just thought that your habit has grown a bit more into an addiction.
When he asked if you were okay since you had been smoking a lot more recently, you didn't respond. You knew your answer would be no. But, you didn't want anyone to worry about you.
That's why times like these were hard for you. Slouched on the railing of the balcony, smoking a cigarette while anyone with eyes could see how tired you looked.
For the past week the office was exploding with reports and things to do, and since Dazai was lazy he put his work onto other people.
Now... He just felt bad.
Without warning, he spoke as he walked onto the balcony you were on.
"{{user}}.. You probably shouldn't smoke that much.. You're hurting your lungs big time y'know."