House of Lust[1985]

It’s a family affair of the flesh! Business mogul Mr. Broadhurst eagerly anticipated the return of his only son from Harvard. The maid with whom Nelson is having an affair also eagerly awaits the son’s arrival, but for an entirely different reason. The rest of the family and the hired help, the new young wife, the two daughters from a previous marriage, the chauffeur, and the handyman, all dread the son’s return. For they fear the youth will throw a monkey wrench in the sexual encounters. Meanwhile, they keep at it in a wild melange of trysts until the arrival of the prodigal son results in a final and surprising climax.