There is a special tool for this, and it isn't expensive.  I got mine
years ago at a VW parts store.  It is a 3/8" drive 1/2" thick disk with
"ears" on it that engage at the edges of the slot in the plug.  You can
hold it in place with pressure on your ratchet drive using a short
extension.  It is the best way to get proper torque for re-installing.
Some VW parts stores even rent them.

Stuart