I think what we realy looking for is a game like Housewife like it was already mentioned before. A hot milf as a mother with a young son (MC). The son (MC) is trying to fuck his mother because he is into her. While trying to acomplish that goal he has to do certain things like make her feel horny aroung him make her laugh help her out... etc. Step by step she getting weak and her sexual interest in her own son rises.
You can also add little side stories in which the MC fucks other milfs. Anoter idea is that the MC grandfather (Father of his Mother) comes to visit and we see how his grandfather fucks his Mom. You can also add a family dog who is fucking the mother. What realy woud be nice as well is when the mother would wear hot lingery something like stocking , fishnets...etc. Diffrent sex locations like in the car (like in refuge roadtrip), in the bathroom, in a retaurant or in the forest would be charming too.