Watched it long time ago. Can't remember much of it. Its about a family with mom, dad, son and that get a housekeeper or a maid and daughter maybe. And boy fall in love with maid wile she fall in love with dad. And one night boy goes into her room and satisfy her with fingers wile she is lying on the bed. And he is like aaw its so cool and she is like noo we can't do this go away xD

Rambling Rose (1991)
Starring Laura Dern, Robert Duvall, Diane Ladd (Dern's mother), Lukas Haas
IMDb synopsis:
In the 1930s, Rose is taken in by the Hillyer family to serve as a housemaid so that she can avoid falling into a life of prostitution. Rose's appearance and personality are such that all men fall for her, and Rose knows it. She can't help herself from getting into trouble with men. "Daddy" Hillier soon grows tired of Rose's rambling ways.

Rambling Rose (1991) - IMDb (http://www.imdb.com/title/tt0102753/)

You can read a debate about what happens with the boy and Rose on the IMDb forum; the thread is titled Was Rose a Sexual Offender?