An ass kicking fiesta is essentially a beating given out so exuberantly and jovially that it eventually takes on a sort of party atmosphere. Ass kicking fiestas are not often witnessed, as most beatings are at least a little difficult to give out, but if you want to increase your chances of seeing one your best bet is to attend any high school basketball game between a predominantly black inner city school and a small, predominantly white rural high school.
"Hey man, did you go to the New Oxford game? They played York High."
'Nah man I figured it was pretty much going to be an ass kicking fiesta for York High, so I skipped it.'
"Well you were right not to go, because it was an ass kicking fiesta of epic proportions."