1- Since there are very few Iranian whores, comparing to other nations (except Arab countries), this is suggestive of something that is rarely found, but at the same time, is of good quality.
2- Since it is very unlikely that you can run into an Iranian whore, this definition is used to say that you don't belive what speaker is saying (should be used in an expression, like example); mostly used in BC.
1- Gee, that piece of jewelry is just an Iranian Whore!
2- A: Guess what; I went to the bar last night and finally ended up in bed with 3 lesbians...
B: Oh Yeah! and then you've fucked and Iranian Whore!!