WHEN Laura Hunter welcomes up to half a dozen fellow mothers to her suburban New Jersey home for an afternoon children’s play hour, she follows a strict routine. The children are ushered into the playroom or garden and given cups filled with apple or orange juice. Then Hunter gets out her real glasses and pours margaritas for the mums.They have become known as the Mommies Who Drink, after the title of a new book by Brett Paesel, a California writer who urges mothers not to sacrifice their lives to child-rearing. Their cocktail of choice is the “momtini” — a potent...