[From Sex, Society and Medieval Women by N. M. Heckel]
De Secretis Mulierum: Evil Women
O my companions you should be aware that although certain women do not know the secret cause of what I shall describe, many women are familiar with the effect, and many evils result from this. For when men have sexual intercourse with these women it sometimes happens that they suffer a large wound and a serious infection of the penis because of iron that has been placed in the vagina, for some women or harlots are instructed in this and other ill deeds. . . .
Here the author discusses some noteworthy points. Some women are so wary and cunning that they take iron and place it in the vagina. This iron wounds the penis, but the man does not perceive it at first because of the exceeding pleasure and sweetness of the vulva. Afterwards, however, he feels it.
Pseudo-Albertus Magnus. De Secretis Mulierum (On the Secrets of Women). Trans. Helen Rodnite Lemay. Albany, NY: State University of New York, 1992.