Kasandra Stephens pleaded guilty in a Japanese court to mailing cannabis oil to her son, a U.S. airman on Okinawa, and to possessing weed when she went to visit him in Japan. Stephens admitted that she mailed a couple of packages to her son’s PO Box after his wife asked for “pens” she could share with a Japanese co-worker, presumably referring to vape pens. The dutiful mom proceeded to mail a package containing 2.88 grams of cannabis oil, which arrived at Tokyo International Airport in mid-August. Several days later, it was sent to the Kadena Air Force base where Stephens’ son, Sgt. DariusOmar…