Quote Originally Posted by Bald_J_and_F
blackmail doesn't work if what is being asked of the person that is being blackmailed is worse than what he or she is being blackmailed for. some authors seem to forget this

That is certainly true but the commodities traded in erotic fiction are not directly compareable (think apples and pears) what is the value of say : your employment and social standing compared to regular sex with a person you hate?

It's hard to judge such things but there are certainly hard limits what can be asked and what cannot. For example many (bad) blackmail stories I read had the victim bring in a sibbling or lover into the same predicament. My understanding of human nature says that this would be one of the things you would never do. The protective instinct would rather have you "sacrifice" yourself.