OBD-042 - 近親中出し凌姦！お母さんの奴●になりなさい！ 美神さゆり

I've mentioned this in reviews for other entries in this series, but given the title and cover art, you expect Mom=S and Son=M, but in reality, Mom is the M. At the very end, there's a scene like 'Become my slave' as the title suggests, but it ends just as it's getting started. I really wanted to see what happened after that...