The main reason is that when you stand upside down, most of the semen will be in the vagina and the part that goes out of the vagina will be reduced, which is good for pregnancy. Also, don’t stand up immediately after intercourse, because if you stand up, most of the semen will flow out of the vagina, which will reduce the chance of pregnancy by 50%. After intercourse, if you have a forward-flexed uterus, the cervix will be pressed against the back wall of the vagina, so it is recommended to raise your hips. If the uterus is posteriorly flexed and posteriorly inclined, the cervix will be close to the anterior wall of the vagina. It is recommended to adopt a prone position after intercourse, which is beneficial to pregnancy, because the angle between the cervix and the body of the uterus will be reduced after adopting a prone position, and the cervix will be soaked in semen, which will shorten the path of the sperm into the vagina and increase the chance of pregnancy.