Zombitch

The protagonist and his mother, Chizuru, were trapped in their home for months by a typhoon-induced landslide... and somehow their sexual desire became abnormally heightened, leading them to engage in forbidden physical relations!

One day, they finally managed to get outside... only to find the world had lost all order,becoming a world overrun by “Zombitch”! These aren't zombies that eat people, but rather “mindless nymphomaniacs”!

They roam the streets in sexy outfits craving men, attacking any they see, enjoying fucking them senseless and infecting them with the virus~!

The protagonist, venturing out for supplies, gets caught by them repeatedly. He falls into a hellish yet pleasurable abyss of threesomes, foursomes, double blowjobs & titjobs, triple footjobs, and more! Yet somehow, he remains uninfected and sets out to unravel this world's mystery!

Meanwhile, Chizuru, guarding the home base, fends off hordes of male zombies craving female flesh using non-infectious play like titfucking, ass-fucking, and dry humping! But sometimes, outnumbered, she can't hold them back!?

What will become of the mother and child, and the fate of the world!!!

[From official site]