Since discovering this thread my imagination has been working and I have a slightly different scenario involving an unfortunate mixed couple.
In a brutal dictatorship a foreign married couple go into business with the spoiled daughter of the Dictator. The business is successful and the Dictator's daughter decides she wants the business to herself. She persuades her father to have the couple arrested on false charges of spying. They are arrested and taken to a secret interrogation centre - their disappearance goes unnoticed.
They are tortured for information but, being innocent, have no information to give. The Dictator's daughter personally oversees their interrogation making sure that both of them have to witness their partners' ordeal!
The Dictator's daughter likes to degrade and humiliate them sexually - she likes to watch and has the sessions recorded so she can watch them in private.
They are both stripped naked - the husband is blindfolded and suspended upside down his legs bent double and secured to a pole spreading his legs wide apart - his arms are locked behind his back. His wife is forced to perform oral sex on him, sucking his cock until he comes in her mouth. Later she is forced to wank him off until, again, he shoots his load to the delight of the Dictator's daughter and the guards!
Then the roles are switched - the wife is now suspended upside down with her legs spread wide. Her husband is forced to use a variety of vibrators on her cunt and asshole - while she is being violated, the Dictator's daughter teases and torments her - she also makes her suck her husband's cock again while hanging upside down.
They beg for mercy but the Dictator's daughter enjoys spending several weeks working them over.
Any artists out there want to illustrate that scenario?