Noun:
1. The off grid medical procedure of using onesthumb to plug a wound if no medical aid is close by and a tourniquet is not available or not practical in a life or death situation.
Slang Terminology
2. It has been brought to the attention of some that this is also a new sex position...
Stick a thumb in it, it will stop the bleeding...
or
"You're getting the Kentucky Plug tonight"
A sex position where, while hitting it from the back, you blow your load inside the woman's vagina, then yell "JUST PUT A THUMB IN IT" and without warming, slam your thumb into her asshole.
Scott had an explosive load and preformed the Kentucky Plug while having sex on a folding table