Sex

Woody Allen told us about the things we wanted to know but were afraid to ask, but there are many things we didn't know that we didn't think to ask about; a case of Rumsfeldian unknown unknowns.
Once you've had sex -- successfully in the procreative sense rather than in the Kinsey sense -- many people will tell you that nine months later you need to do it again, to see the result of what you put in come out again.
Why? Because your sperm (yes, I'm addressing an exclusively male audience in this post, except that women ought to recognise that we know now) contains prostaglandin , a hormone-like substance that is supposed to induce birth. So it makes sense for you to mount / be mounted by the bearer of your child (even with your cracked ribs) to end procrastination. However, the prostaglandin doesn't need to go in that way. The hormone simply needs to be added to the expectant mother's body, and she can quite easily ingest it without the need to come to blows, so to speak.