To 'buckweat' someone means to murder them in any method that causes a slow, very painful death. The phrase 'buckwheat' was given rise to in the film ''Things to do in Denver when you're Dead''. (An excellent movie which I highly recommend).
One example of a 'buckweat' is to fire a gun into someone's rectum. This causes them to contort and suffer excruciatingly for 20 minutes before they die.
by BadLieutenant June 07, 2004
To shoot someone in the asshole with a small gun, usually a .22, and cause their hair to stand up in great pain. To kill with extreme predijuce.
"Little Sambo just got his 10000th free buck from Uncle Sam. And so to help him celibrate I thought what better way to spend a bullet and save the tax payer some dog."
by Wayne Williams August 22, 2003