Senza scrupoli (1986)

A woman who has just separated from her husband, comes to stay at the villa of a friend. The friend is away (and throughout the whole movie is only heard as a voice on the phone), but the woman's goofy son is staying there too. The son falls for her, not surprisingly since she always dresses in skimpy miniskirts or bikinis, and rarely closes the door when she is changing clothes or showering.