That it’s much easier to conceive, and women are much more fertile, when they’ve just given birth. Loads of people think “hey ho, her period hasn’t started again yet, let’s go for it,” hence loads of siblings born a year apart.
You need to pee after PIV sex if you’re a woman. It can prevent urinary tract diseases.
If you’re going to have fun with whipped cream, don’t actually use whipped cream, or else you’ll smell like sour milk for a day or two, even if you shower. Use Cool Whip – it doesn’t smell, and it also doesn’t melt the way whipped cream does, so there’s less chance of it sliding off or getting the bed messy.