One night and two days of 1 night and left alone by my wife's sister who suddenly came over

While Tatsuya's wife was pregnant and went back to her hometown, she enjoyed living alone for the first time in a while. However, living alone began to feel lonely after just a week, and as I was falling in love with him... my sister-in-law Tsubasa came to help out with the housework. Tatsuya welcomed the sudden visit. However, Tsubasa's true purpose was to relieve his frustration with Tatsuya while his wife was not returning home. Tatsuya, who has no idea about such a plan, is soaking in the bathtub with ease... and wings start to enter...