Freed points out that, in the romance languages, Tuesday is named after the planet Mars (like Martes in Spanish and Mardi in French), and that Mars is associated with energy, action, and desire. “If you don’t use your Mars in a sexual way, you may find yourselves bickering and irritated with each other,” she says. And don’t wait till lights-out (when you’re likely going to be exhausted). Instead, have a quickie when you both get home from work. “Dinner can wait,” says Freed.