The cervic thrashes about a bit during every orgasm of the fairer sex, and I've heard tell of certain women who can go straight to orgasm 'you may pass go and collect £200' from some skillful manipulation of the cervix...
bit medical, and ancient, but hay ho...
"Joseph R. Beck, physician, 1872, upon examining a women with uterine prolapse, who warned the physician to be careful, as she could reached orgasm very easily, even with the pressure of his finger.
“separating the labia with my left hand, so that the os was brought clearly into view in the sunlight, I now swept my right forefinger quickly three or four times across the space between the cervix and the pubic arch, when almost immediately the orgasm occurred…Instantly the height of the excitement was at hand, the os opened itself to the extent of fully and inch, as nearly as my eye could judge, made five or six successive gasps, as it were, drawing the external os into the cervix each time powerfully, and, it seemed to me, with a regular rhythmical action, at the same time losing its former density and hardness, and becoming quite soft to the touch. All the phenomena occurred within the space of twelve seconds of time certainly, and in an instant all was as before. At the near approach of the orgastic excitement the os and cervix became intensely congested, assuming almost a livid purple color, but upon the cessation of the action, as related, the os suddenly closed, the cervix again hardened itself, the intense congestion was dissipated, the organs concerned resolved themselves into their normal condition.”
Joseph R. Beck, “How Do Spermatoxoa Enter the Uterus?” St. Louis Medical and Sergical Journal 9 (September 1872): 449."
http://alt.com/magazine/advice/2535.html?show_erotic=
http://www.after-glow.com/vaginal.html