When you hit a rough spot with a good friend, what do you do about it? Aminatou Sow and Ann Friedman are longtime friends and business partners. Their fans also know them as the hosts and creators of 'Call Your Girlfriend,' a podcast “for long-distance besties everywhere.”When they recently hit a rough patch, the pair took what might be considered an unusual step to save a friendship: they went to therapy together. Their new book is called Big Friendship: How We Keep Each Other Close. They talked with Greta about writing it together, the scholarship of friendship, and where their relationship is today.