Solved.
It's a story about a wife and a daughter conspiring together to get the father to have sex with the daughter. The wife has the daughter pretend to take some sort of medication that makes her fall asleep. Then the wife and husband start doing sexual stuff to the daughter while she's pretending to be sleeping, escalating into the father taking the daughter's virginity in her sleep. Some point after that the daughter and wife come clean somehow and they all live happily ever after.