Stop that at once

[webofevil]

It is a mortal sin for a husband and wife to have intercourse with the normal position reversed, because it makes the woman active, which, as anyone can see, Nature must abhor. Furthermore, according to certain authorities the Flood was caused by the vile custom of women mounting upon men in the sexual act.

Thomas Sanchez (Jesuit), De Sancto Matrimonia (early 16th century)