A fictitious account of events that has been created and repeated consistently- often over a period of years- with the intent of having that story become accepted as fact. The ultimate goal of a Taft's Buttplug is to someday hear the fiction you created be told to you by a stranger as if it were fact.
The phrase itself originates from the story that President William Howard Taft, the most rotund President ever, was fitted with a balsa wood buttplug which he used to prevent his typical flatulence at State Dinners and the like. The buttplug was/is reported to be in the basement archives of the Smithsonian. In reality, the buttplug likely never existed, as the first documented report of the alleged buttplug was by an ardent Teddy Roosevelt supporter during the height of the split with Taft.
Remember when I stopped to help that hot chick change her tire and she did me right there by the side of the interstate?
Thing is, that never happened. It's a Taft's Buttplug.
A sexual act, originally involving a Rocket Pop but later including most any frozen treat on a stick, whereby the frozen treat is inserted rectally and then snapped off of the stick.
Whew, it sure was hot today. Think I'll unwind with a margarita and a cold snap.