After her boyfriend's mother unexpectedly dies, she leaves him a kitten.
He feels sorry that the kitten was taken from its mother too soon, so he decides to nurse it himself.
He has no breast milk, so the kitten bites him until he's bleeding and infected. Even when he's facing an amputation, he refuses to give up nursing it.
"Maybe you should stop feeding it. It smells awful down there, and the cat's suffering too!"
"Rourou, you're a woman. You feed the cat, okay?"
When I refuse, he ties me up, gives me drugs to induce lactation, and locks me in a basement to torture me.
Until I accidentally fall into the level below and see his mother.