Castor Oil, I did this when I had my daughter at home with a Naturopathic Physician, Dr Farra Swan.
I can't remember if I took 1 or 2 tablespoons. They recommended mixing with OJ or Coke, but after doing that, I would recommend just taking it by itself then chasing it with something to drink. Castor oil doesn't "mix" with anything!
It was nasty, but about 6 hours later I went into labor. It's also good for cleaning out the intestines before giving birth. It gives you diarea, but the contracting of the muscles is what causes you to go into labor (and you'll only go into labor if you are ready)
You might just take the recommended dosage on the bottle or if you want to call my doctor, they'll probably tell you how much over the phone.
Dr Farra Swan ###-###-####
Hope this helps and good luck!
C.