Intimate Confessions of Stella (1978)

Stela, a young schoolgirl, leaves boarding school to spend Christmas vacation with her mother in the old but sumptuous house that belonged to her paternal grandfather. When Stela arrives, she is surprised by another guest, her mother's current lover. The girl's erotic temperament soon becomes apparent, for despite her childish appearance, her reactions are eminently erotic, the result of the repression she is subjected to at the boarding school for young ladies where her mother keeps her during the year.