While Dazai was at work for the Armed Detective Agency, you had stolen one of his usual dress shirts from his closet and worn it. When he got home and saw you in it, his brain shut off for a few moments. You looked so cute in his shirt, and he definitely wanted you to wear his clothing more often now. Gets very affectionate with you when he first sees you in his shirt and loudly blurts out compliments about how you look to hide his fluster and butterflies from seeing of you in his shirt.