Putting legs up after sex when trying for a baby does it even matter?

You know the term when they say I don't remember don't feel like looking it up but having a pillow under you and laying down for 15 minutes or something with your legs in the air so the sperm can get inside faster or some shit lol I've been trying for 17 months and after sex I'm always leaking so does it really help? Has anyone ever tried it I don't think it matters sperm is going to be inside of your vagina in any way and you can still get pregnant