Doberman Pinscher Flank Sucking (IMAGE) Tufts University Caption This is a Doberman pinscher flank sucking, an example of canine compulsive behavior. Credit Courtesy of Tufts University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.