Being a fur is a serious slippery slope to things even worse, like yiffing or whatever perverted fantasies you might be in.
Just fyi, "yiffing" is a (rather weird) slang term that litteraly means "to have sex." It's only as specific as that. So, sure, "to have sex" is a perverted fantasy, but not really a unique one :/
NSFW: http://www.google.com/search?gcx=c&q=yiffing&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&hl=en&tab=wi&biw=1280&bih=685
