A tactic used by employees to share blame or divert blame should something go wrong. "Covering your ass" is usually done in big projects where an employee may choose to avoid taking credit for doing a critical part of the project just in case it goes bad. For example, if the acceptance or rejection of a crucial project relies on your forecast of cash flows for future years, you may include a footnote that your estimates were based on data provided by another employee in case your forecasts are completely wrong. This practice is often frowned upon.