Lately, Yuki has been masturbating alone more and more, not being satisfied with her husband's sexual relationship. One day, Yuki witnesses Atsushi, her son-in-law who lives with her, secretly masturbating every night... Yuki is instantly Kokoro by his huge, powerful cock, and offers to satisfy his sexual needs "in place of his daughter who won't let him." From morning until night, whenever he gets the chance, his mother-in-law sucks on her son-in-law's huge cock, milking him repeatedly. And Atsushi is made to cum so much that he can't think with anything but his lower body...