<---Newbie here, but I never heard it grows bigger bud...
but it sounds like he's talking about Low Stress Training (LST). you bend over the plant's growing tip down using string or wire, not upside down, just at 90 degrees. but it will turn back up to grow toward the light. the process keeps it short.
don't know about increase in yeild. i hope so, i use LST alot.