When the balance is so uneven between two teams such that noncompetitive game and a thorough defeat is virtually guaranteed. Usually used in a choose-up selection process where one captain picks players or selection is done by letter or number but the result is two unevenly matched teams. The term is used to demand a reselection of teams.
You guys can't have Pete and Max and Jake, them's slaughter sides.
Guy 1: "Yobois did my girl come thru last night?"
Guy 2: "Hahaha yeah man i fucked the shit out of her"
Guy 1: "Thats not very slaughter gang of you bruh"