This is another good topic, Lee. I think it could go either way in fanfic and has. One could imagine a set of circumstances where Napoleon makes the first move and an equally plausible scenario where Illya does. While Illya is not the ladies' man of the show, this does not mean he is clueless, gay, or finds sex less important. He may, in fact, take sex more seriously-- or not. These attitudes are subject to interpretation and hardly cut & dried. They both flirt with each other on the show and it is possible to see how they would handle this spark between them from various and opposite directions. There's just not a simple or obvious conclusion to be drawn.