MUGON-060 I got excited about my sister sleeping in a suitable loungewear

One hot summer day, when I got home, my older sister was sleeping in a sloppy outfit. Light clothes that are too defenseless, sweaty skin, clothes that roll up every time you toss and turn. The sight of her sister, who should be familiar to her, sparks interest and a strange excitement. There is no sign of getting up. Even though I thought it would be bad if I got caught, it escalated...