In the Role-Playing-Game community: A dicer is someone who rolls a die a certain way to receive a desired number. There are several dicing techniques, including the drop technique where you don't actually roll the die, rather you just drop it with the desired number showing on top. See Dice and Dicing
Kenny: You killed me again. I'm never playing with you again because you are a Dicer.
I term created to demonstrate the lack of originality and relevance in todays insults. Similar to "tool", "plug" and "duster", this word has literally no meaning whatsoever, other than the fact that is rolls off the tongue nicely.
Dude, I called this guy a dicer the other night and he urban-dictionaried it to see what it meant! What a dicer.