Don’t talk to me about the wisdom of the ancients:

“And it is absolutely NOT necessary for wives to move at all. For a women prevents and battles pregnancy if in her joy, she answers the man’s lovemaking with her buttocks, and her soft breasts billow forward and back; for she diverts the ploughshare out of the furrow and makes the seed miss its mark. Whores practice such movements for their own reasons, to avoid conception and pregnancy, and also to make the lovemaking more enjoyable for men, which obviously isn’t necessary for our wives.”

Lucretius (60 B.C.)

Found via a link over on Tiny Nibbles.