Squatting and Sneezing
The Ancient Greeks may have given us the roots of democracy, the first Olympic games and advances in architecture we continue to use in our modern society, but they also gave us this doozy of a way to prevent pregnancy: sneezing.
Greek physician Soranus may have doubted the contraceptive qualities of amulets, but he didn't shy away from suggesting trying to shake the sperm out before it could fertilize a waiting egg. Not only was sneezing recommended, but squatting, jumping up and down, or even kicking your feet against your own bum were prescribed as effective birth control methods. As we know now, even if you sneeze after sex you can still become pregnant.