From Tyler Cowen over at Marginal Revolution:
These demand curves are the exception rather than the rule, but nonetheless they appear to exist:
One sex worker...explained why she no longer offered her favorite clients free sex or cheaper rates: "They pretend to be flattered, but they never come back!...There was one client I had who was so sexy, a tai-chi practitioner, and really fun to ****. Since good sex is a rare thing, I told him I'd see him for $20 (my normal rate is $250). Another guy, he was so sexy, I told him "**** for free." Both of them freaked out and never returned...They don't believe they can have no-strings-attached sex, which is why they pay. They'd rather pay than get it for free."
That is from The Purchase of Intimacy, by Viviana Zelizer.
I have two reasons why I doubt this is an example of a Giffen good:
1. The guys are not getting the same good - no-strings attached sex is not the same as strings-attached sex. It seems the men are using price as a signal to ascertain something about the girl. The low price could well mean that each thinks there are more likely to be strings attached.
2. For a good to be a Giffen good, it needs to be an inferior good. Is it reasonable to assume that when the average income of consumers of sex fall, they are willing and able to buy more sex?