I was there, too, as you know. It is good to see it written down with all the comments and explanation Roni gave. I wonder if the Rabbis meant when the virgin is bathing in the tub with the same water where a man was bathing beforehand. It sounds like what my grandma was told when she was a young teenager. They thought women and girls could get pregnant if they sat down on the same stone as the men sat before. She talked about a kind of bath house in Iran. In Muslem countries they don't have sexual education either. I doubt that it is better nowadays.