after sex..."marinate" or clean up?

My friend told me that in order to get pregnant that I should "get drunk (no thanks, not for me) have hot sex with the hubster and let that sh*t marinate." She was drunk while giving this advice. How many of you clean up directly after or just lay there? Does it matter if you get up to clean yourself? Does gravity make it not reach the egg? I am prone to UTI's and I'm always scared I'll get one if I don't go pee directly after. We've been trying this "let it marinate" theory but I always feel yucky not getting up and washing off! 
I didn't test this week but just used the app to see when my fertile days were. Hopefully this month is the month we are blessed with baby. I should start my period around May 10th. I go to see my doctor on May 1st for my annual check up. If I don't have good news by then, hopefully she can run some tests and see if I have any problems. Wish us luck! Xoxo