https://www.dlsite.com/maniax/work/=/product_id/RJ01253958.html

[Synopsis]

While he was sleeping at home after skipping college, his mother was attacked by a burglar.
However, he was too scared of the burglar to go and help her.
After much conflict, he was the worst son and could only watch until the end.
Furthermore, he became aroused by the sight of his mother being raped...
The burglar's sperm had already been poured into his mother's vagina.
To top it off, his mother was asleep and showed no reaction when he called out to her.
Seeing this as a golden opportunity, he blames everything on the burglar and indulges in all his desires towards his own mother!

Base +25, rikudosennin +6, wudilugubaolei +5, kishudark +6

The good son washes away the burglar's sperm with his own!

Base +7