First you pour diet coke in a girls vagina. Then you grab a handful of mentos and fist fuck her for a count of three. Do not count to four, nor two, lest it proceedeth you to three. Five is right out. Then get the hell out of the way.
"The other day I was fisting my girl and she said 'hey, let's try something kinky' so I gave her the Holy Hand Grenade. I was cleaning diet coke off of my walls for three days.
Killing yourself or others during a video game. Commonly used in First Person Shooters and the use of explosives. Has also been known to be used when a player makes a dire error without the assistance of others.
During an assault on the Red Base, a player named Duffie poorly threw a grenade inside the base. The result was a ricochet back at the player which managed to kill him. Overall it was a failed assault to say the least...
The event was escalated after another player known as Smith witnessed the entire episode because he was in fact dead himself to begin with. Since then the term has been spread to many other games and uses.
Other similar terms: Duffie Grenade, Duffy Grenade. Commonly used as a verb: Duffing, Duff'd.
You nearly manage to hurt or kill yourself during a FPS game.
After throwing a bad grenade or other explosive you reply, "I duff'd it." In warning to others that you just f*cked up. True sense of the term the Duff Grenade.
While in a tank, you manage to effectively kill your entire squad with an ill advised shot. A severe duffing.