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

Kenta was in a state of trouble. The cause was the strange behavior of her sister-in-law, Rena. It's fine to see that while my wife was pregnant and went back to her hometown, she came to help with housework. However, there are too many mysterious actions that follow. He lets out his back and comes into the bathroom naked... (Is he really inviting him?...No, isn't that the case?) Kenta concludes that he is just teasing Rena's mysterious actions. With her frustration in her heart, she went into bed...and then Rena came...