What does it mean to "tap" a drain plug thread?

[jackelope]

Do what you want, but it really is easy to install one of the oversized selftapping ones.

Think of it this way:
  *  America was built by men who could install a selftapping plug.     
  *  Trump would just pay someone else to do it.

We refuse to install these at my shop. Too much liability. If it fails, you're ultra screwed. If the shop installs it, they're on the hook for it.
Ain't happening....

[Bean Counter]

Update: With a gentle pull of the pliers straight down, I was able to get it off with the socket.

How bad is it, doc? 

Definitely don't try to tap anything. You really need to be looking at the condition of the pan itself and not the plug. Those plugs are designed to do that. You'll ruin the plug before you ruin the pan. What's the threads in the pan look like?

To be honest they kind of looked like the drain plug. but, I got the new one in there! 

SUCCESS.

Thank you, Hive Mind. You have helped me stay true to my inner city, Section 8 Housing roots.

[mazama]

My old memory has kicked in,I was told years ago that oil plugs were softer than the pan so that they would strip before the pan would.

[timberghost72]

Unless the pan is aluminum.