Orgy Slaves by Don Elliott

LUST TRIO...
... the three wantons shared their apartment of shame with any and all takers. Kate, Bonnie and Lois, manufacturing their own perverted past-times when nothing else was handy, or engaging in depraved orgies where any number, any combination, could strive for individual ecstasies. Into this weird menagerie stumbled Ray Hollis, a virile lover, seeking to put aside degradation and settle for true love ... something he couldn't hope to discover inside the --
... SHAME DEN!