Several years ago I encountered a stripped oil pan drain plug. I discovered what is best described as a rubber bubble ['think bubble gum bubble'] with a large head and a 'pipe' in the middle. To use it, you used a pencil, dowel or something, to put inside the 'pipe' and push, thus enlongating the bubble, insert into hole and remove the dowel. The bubble would expand on the inside and not leak a drop of oil. Due to the time involved I don't remember where I found it, but I'll bet most any car place has one like it. If they don't they should.
USN Retired Aviation Electrician, Ham call K9GKL
1998 Fleetwood Discovery 36T, Cummins diesel.
2009 HHR w/ Air Force One