A term that is gaining popularity in first-person shooter online multi-player games like "Modern Warfare: 2". "Coffe Grinding" is the act of, upon a successful kill of another player, crouching over the head of the victim's dead body and proceding to perform a "grinding" motion leaving behind a residue of feces with the consistency of "used coffee grinds". This act is to shame and humiliate the victim player, and usually incites anger and violence. Normally performed when one player is "owning" another or a team of others.
After I knifed him for the 4th time in a row I felt like coffee grinding that loser as he bled out on the floor. I ran over and coffee grinded my ass all over his face and then knifed him again.