The girl who is 'no supermodel' caught my attention. The idea of being a chasity slave to a female who is less than your ideal type is particularly exciting. It could even be a girl who he had previously rejected. Or someone older. Or someone who was 'too swarthy' for him.
I don't do too many of them, as they are not quite my cup of tea, but ptathuk, who inspired me to do this blog, does a lot more.
If you're going to have an inspiration, ptathuk is the best you can get.