There is a certain possibility of pregnancy during ovulation with extracorporeal ejaculation and there is no guarantee that you will not get pregnant. This is because when a woman ovulates, she will normally discharge a mature egg, which will conceive if it can meet with sperm and combine to form a fertilized egg. Because of external ejaculation, the penis is already normally erect and enters the female vagina normally, while the male penis with an erection will secrete a small amount of prostate fluid, which contains a small amount of sperm. So if you are in the ovulation period, just by way of external ejaculation for contraception, the success rate of contraception is still relatively low, but compared to internal ejaculation, because the sperm content is after all very little, the possibility of pregnancy is much smaller compared to internal ejaculation.