Looking for Doujin

Hello! Looking for the name of the doujin where the father sells his daughter (loli) off to a co-worker who has a pretty big penis. The father then suicides himself and his wife in a crash. (the other guy finds out in the end) During the whole thing he trains her with his big penis sexually and eventually into anal into making her his slave. The other books are about a brother and little sister learning to love anal/etc. (big penis again)

Sounds like yukino yukikaze under 9.
Here's a link the chapters your looking for starts on page 123

https://hitomi.la/galleries/331485.html

I love you! Thank you so much, I forgot the name Under 9.