When a quite large muscular thumb is used to penetrate a desired orifice, can be used in a sexual manner or just may save your life, but it's mostly for the memes. Comes from when Scott Allen DeShields, Jr., whose YouTube channels name is Kentucky Ballistics, had an unfortunate accident involving his RN-50 exploded causing a piece of shrapnel to sever his jugular. The use of his thumb jammed into the wound cavity putting pressure on his artery is what saved his life. His optimistic humor with the phrase "put a thumb in it" has led to the creation of this term.
Saved by the Kentucky Plug. That's a lot of damage, but is it too much for the Kentucky Plug.