1. To complete a form or record, especially a checklist, without doing the work required or by providing falsified or incomplete information. It has come to light that the safety supervisor aboard the oil rig had been pencil whipping his observational reports for several weeks leading up to the disaster.
2. To approve such a form without actually verifying that the contents are accurate or properly completed. We're supposed to fill out a detailed checklist after each shift, but I know my boss just pencil whips them.