When someone takes their thumb and shoved it deep inside a whole.
After a severe accident with a .50 cal exploding a Kentucky man was able to save his life by plugging his thumb in his neck to stop bleeding. After the incident many loving fans made memes in support of the man and his recovery. One of which is now the Kentucky Plug which seems to have been taken in many different directions...
My girlfriend said she’d let me do the Kentucky Plug if I didn’t bring up politics at thanksgiving this year.
When the thumb of a big bald burly man is jammed with significant force into a natural or unnatural body cavity preventing the cavity from leaking its contents...
“Yeah man, Ellie started her period halfway through the hookup, so I gave her the ol’ Kentucky Plug”