Penthouse Party by Gerald Kramer

'The exotic drink was no less intoxication than the erotic prospect of letting them share her.'

From the back:

The Voluptuaries
They lived in the most luxurious of Park Avenue Penthouses, hiding their corruption beneath a veneer of elegant sophistication, spicing their jaded lives with sordid experiments in raw sensuality
BARBARA . . . the young bride who crept out of her husband’s bed and into one occupied by a naked woman.
SIMON . . . the affluent producer who enjoyed introducing pretty girls to his brand of dark sensuality.
JANIE . . . the oversexed teenager who couldn’t say no to anybody . . . or anything.
JACK. . . the muscle-man who specialized in catering to the gasping needs of older, wealthier women.
DELORES . . . the glamour girl who amused herself by taking husbands away from wives and wives away from husbands.