When you have sex the sperm and semen contain stuff to help soften your cervix.
They say during sex you produce a hormone that helps soften your cervix. Castor oil either helps you start labor or go to the bathroom. Spicy foods there's a compound in spicy food that is suppose to help start labor. I read an article on what to expect about getting labor started and those were on the list.
Castor oil is dangerous, it can make the baby have a bowel movement in the womb and cause a bad infection in the baby.