Kitagawa Erika is like the sweetest Mom ever and she has been raising a son by herself doing fine, but lately, the son seems sad. What happens is that the soon is being bullied by 3 schoolmates who have been escalating their bullying.
Eventually, the 3 dudes decide to crash on Erika’s son’s house to keep the bullying fun going on. And there they meet with the Mother. Who initially is glad that her son has “new friends”, but she couldn’t be more wrong. Because the 3 punks are out of control, and it doesn’t take them long to notice Erika’s sweet ass.
After that is 4 hours of gangbangs, basically. And don’t take me wrong, it’s a truly awesome video.
The doujin itself is called Sacrificial Mother I believe. (“いけにえの母”). From Yojōhan shobō (四畳半書房). A video that followed from the same author was URE-035.