The older brother discovered his younger sister masturbating and it ended

Riko, a female student, a stepbrother, and a simple NEET guy … The two suddenly came to live together under the same roof when their parents remarried. The dull brother Niriko suddenly deciding to live together is a drag. Riko is forced to have sex with a secret electric massager and masturbate in her room for 3 days while her parents are away on a couple's trip. However, there is an unexpected coincidence between the two … Riko and my brother's gender compatibility is really the best. My rebellious tsundere sister is brought to tears by her disliked brother-in-law!

The older brother discovered his younger sister masturbating and it ended