It does not work!! My husband and I use this method, and have for 3 years. We don't have sex more than once in 48 hours... And he doesn't masterbate before sex eother(I know this cause he doesn't want children for another few years) we however didn't track ovulation but figured only having sex once in two days, would protect us from pre-cum. And he pulled out everytime at least 20 seconds before cunning.  We are excited even though it was a complete surprise!! Just wanting to let people know this isn't effective as birth control!!