Sex after one child shows down. After twins... ooh... I'll tell you what it is for us. I'll share it with you. Every three months. We don't plan it that way. That's just how it works out. It's the weirdest thing. You know what I do? Every time I have sex, the next day I pay my estimated tax. My quarterlies are due. If it's oral sex, I renew my driver's license.