The vibrating sensation you get when the person you are sodomizing farts across your penis.
"Putting up with the smell was well worth it to get to experience that wonderful Joy Buzzer across my dong!"
After having anal sex and having feces repeatedly rammed into the penal hole, the penis fills up with a string of feces. Then upon taking a leak for the 1st time after anal sex, the skinny strip of feces will come out into the toilet. That strip is roughly the length and diameter of a chocolate french fry, hence the name.
"I forced Bryce to eat my chocolate french-fry as his punishment for not purging his man-gina before having his little hissy-fit and demanding I put the ol' crank shaft to him."