Just my opinion here guys, with the propping up of hips thing... I wouldn't do it on a very steep angle, only because your cervix opening is right in the middle of the cervix (imagine a tiny volcano) and if you raise your hips too much, the sperm is going to pool at the bottom and around the edges and will find it more difficult to get in the opening. Personally i will just lie flat for at least 40mins, but obviously the longer the better.