Female sacrecion kills sperm?

My friend and I were discussing on how to get pregnant! Her mom said that the most fertial day is the 10th day of the begining of your cycle, ok first 3 days were old brown blood and so I didnt think I should count those days! lol I know guys sick huh? lol anyways!!!! so she told me on the 10th day to put a pillow under me and keep that poss for an hour! then she told me that females way of