I agree with Trey but I own the tool in question. The slide hammer is the way to go - especially with certain cranks that are gun drilled. If you have one of those the grease method won't work, you will push the plug into the engine. In the process you will also learn the definition of the word frustration if said engine is in a vehicle.
This is the Cliff's Notes version but I have a friend who can explain this scenario in detail if you like.
