Juzo Itami made a movie titled "Ageman" which literally means "lucky pussy". It was about a geisha who brought good luck to anyone who slept with her. The movie starred his wife who he claims is an ageman .
Then there is Rie Miyazawa. Everyone who has slept with her seems to see misfortune befall on them. Most noteablly Takeshi Kitano whoes face became partly paralized because of a motorcycle accident. She is a typical sageman or "unlucky pussy".
If good luck is considered a welcome trait in Japan, I think it is at least partly because it is thought to rub off on other people.