How about a short story about the image in the link
http://motherless.com/79768B3

You could say that they have been condemned to die for being prostitutes and do it from the point of view from a 3rd party point of view who knows the feelings of each girl. How about this for a plot summary of each character from left to right (I'll come up with some names and ages later; all take around 20 minutes to die):

1. Really scared. Wants to live and struggles violently against the pain until the girl on to her right has an orgasm and then she tries and gets really horny but pisses before she can fully orgasm.

2. Knows that she can get an awesome orgasm out of it and, despite the pain, has a great orgasm before pissing and dying.

3. Doesn't want to seem nervous and tries to orgasm the entire time but pisses instead and is extremely humiliated before she dies. Again lots of pain.

The first three should have a bench kicked out from under them.

4. Like 2 but pisses earlier and then struggles against the pain for around 10 minutes more.

5. Has no self worth and is upset about hanging but not terrified like 1,6,7; doesn't care if she makes a fool of herself like 3 and isn't intent on having an orgasm like 2,3,4. Struggles violently against the pain and has a few small, insignificant orgasms and wishes she could masturbate (but can't) so she can have an awesome orgasm like 1,2 and 4. She then pisses many times.

6. Terrified of hanging. She struggles against the pain and against her orgasm. She pisses before hanging and at the end- but not after her orgasms which make the whole hanging experience even worse for her. She suffers the worst.

The next three are all hung at once- they set off around 10 minutes after the first 3 start.

7. She is the owner of the brothel and is forced to watch as all her employees die painfully. As the owner she does not sell her body and sees herself as a respectable woman- therefore she is shocked when she is forced to strip naked and she is so terrified at seeing her employees die that she feels herself about to piss. She put 2 fingers into her vagina to stop it but is accused of masturbating and when her hand is tied up she pisses- much to her humiliation and the crowd laugh at her and film her. Her hanging is very painful and she doesn't have an orgasm. She pisses at the end to even more humiliation before all the girls are dead. She is hanged separately.

The on-viewing girl is head prostitute at another brothel and she is to be hanged with her prostitutes next week-much to her shock (although she is turned on by the matter her sense of human dignity outweighs that and she is terrified of making a fool of herself.

Just an idea- take it or leave it but tell me if you like the idea.