The word evolved from the word "gank" via the "izn" language (popularly used by rap artists). Why the definition of the word "giznank" became so detached from the meaning of the slang word gank is unknown...
the act of standing with one hand on a hip, a leg partially bent at the knee raising heel slightly, rotate hips toward bent leg, then smile radiantly toward camera with a deer in headlights blank stare
Every cheerbutt girl I’ve ever known does a ginnapose.