I witnessed my sister, who is a NEET mourner, masturbating, and my rationality collapsed. I didn't notice that my sister was cumming and the piston exploded

``I saw it...'' --My sister's room is dirty because she hasn't cleaned it up. I've been wearing the same lame T-shirt since middle school. He reads erotic doujinshi and has poor eyesight. In the end, he became a shut-in and a NEET. A typical widow... Of course, I had no interest in it since they were brother and sister. --Seeing such a younger sister masturbating seriously! At that moment, my sense of morality, ethics, and reason collapsed with a bang. She turns into a sexual monster who is in heat with her younger sister! My sister's dried mourning woman's pussy is also awakened! I had to cum inside my vagina over and over again...