Oyasumi Sex - Episode 4

Since our parents divorced, I spent more time with my younger sister. For me, Yui is still like a little baby. I have to be able to replace the position as a father and take care of Yui. However, over time, I feel insane. Every night I do something pervert to my own sister when she sleeps. I understand we are siblings, but I can't help it.... (Source: Translated and Edited from Nekopoi)