work one's butt off(e.g. You come home from the office and moan: Статью пишу, пашу, как каторжный! => I'm writing an article! I've been working my butt off = >>> literally "working like a convict." || Перевод: M.Berdy, TMT)
work one's butt of(e.g. You come home from the office and moan: Статью пишу, пашу, как каторжный! => I'm writing an article! I've been working my butt off = >>> literally "working like a convict." || Перевод: M.Berdy, TMT)