What is Be Bugging?

In simple words, "Be bugging" is the process of adding known defects to the application by seeding.
Or
The process of intentionally adding known defects to those already in the component or system for the purpose of monitoring the rate of detection and removal, and estimating the number of remaining defects.
Or
If the Project management add some known defects in order to estimate the efficiency of tester, then it is called Be bugging or Defect Seeding or Defect Feeding.