Catch up sex. You know it. It’s a simple concept: having intense and long-winded sex after a time of abstinence. Of course there are many reasons couples have sexless interludes: time when you look back and it’s been weeks or even months for crying out loud. There are surgeries and illnesses, there’s having a baby, living with a baby, living with toddlers (o.k., kids in general), there are long running arguments, and, let’s face it, just a lack of interest. And once the no-sex ball gets rolling for any reasons, it seems that your sex-drive rolls right away with it.