The original usage of twinkie occured circa between fall/spring 1979 or 1980 when I, a female guitarist and actress, was in a punk rock band rehearsing in a "music building" in Manhattan on 38th street. I would pick up a twinkie before rehearsals and eat them on breaks and the singer in my band started calling me a twinkie. That summer I went to work at a summer stock theater on LI where I started using the word around anyone being extra silly or acting out (i.e. doing a lot of twirling or drag, or being fabulous in some way, etc.)...the guys, most of whom were gay dancers, caught onto it. Within a couple of years the word was being regularly used in the gay community for any young, fun partying gay boy. That is the true origin of the usage of twinkie on the gay scene and how it came about as it had never been used in any context prior to that except in reference to the yellow packaged creme filled cake.
You're such a twinkie!