An instrument usually made of rubber that is inserted into ones rectum to help prevent infectious diseases from entering ones body through their anal cavity.
Mother walks in on gay son using buttplug she gave him for Christmas, "wow you've fairly mastered that buttplug son!" to which the son replies "I know, I am the true buttplug maestro."
Someone who is so arrogant and self absorbed that it would seem they spend most of their time with their head shoved neatly up their own arse. Often with a butt plug shaped head and ridiculously small ears.
Andrew is such a buttplug head. He doesn't listen to anyone's ideas except his own.
The act of removing your dip and shoving it up someone's butt hole and proceeding to have anal sex. The saliva soaked tobacco acts as a stimulating lube.
Jimbob: "Hey Maryanne, thanks for letting me give you a redneck buttplug last night! I had the a nice tobacco buzz for hours!"