Re:Sister - Living Together Secretly with My Little Sister

Parents trust the house to a brother and sister while they travel…

You're tasked with cleaning the local shrine in your hometown after the previous caretaker passed away. At first, it seems like a chore, but then you're greeted by the shrine's resident, a fox girl named Mao. She's hesitant to approach you, having been out of touch with humans for a very long time. However, she seems to appreciate your efforts in cleaning the shrine she calls home.
 
Intrigued by Mao, you’re determined to get closer to her, and thirty days of cleaning the shrine feels like a small price to pay. Will you be able to win the fox girl’s heart by the end of your task?
 
Each day, you're expected to clean the shrine, and in doing so, Mao warms up to you more and more. Gaining her trust will unlock new interactions, both with her and with your surroundings. You only have 30 days, so manage your time wisely between responsibilities and spending time with Mao. Raise her trust level to 100 before the time runs out to achieve the perfect ending with this cute fox girl!

The brother and sister that were left to their own devices by their overseas
travelling parents and still at it, enjoying day after day of sexual indulgence.

The protagonist begins living together with his girlfriend Kanako Tsukishima, whom he started dating as a college student.
Compared to sweet romance, living together requires facing many practical problems.
Players plan a daily routine that balances academics, life, and romance.
As a boyfriend, it is also important to satisfy Kanako’s body and mind.
Too much sex will make her hate you, while no sex is allowed, of course.
The 26 weeks that the protagonist and Kanako spend together will determine the ending of their relationship.
The game has an auto-save system.
For the sake of realism, the player’s previous actions are recorded,
conversation with Kanako and her reactions will differ.
If you do not listen to her voice properly, you may be rejected.

The protagonist’s little sister (Himari)
suddenly comes to live with him
due to where she is now attending school.
Himari crashes into this new life
while still being too trusting of her brother.
He shows her things he shouldn’t and acts like everything is fine.
Thus, her life living under the same roof as her brother begins.