You ate ass and you were cool with it, then she went to take a shit "a few hours later"? Then the smell was "like a dead rat had been left to rot for a few weeks". What? The smell coming from the bathroom? Did you attempt to eat her ass again before she had time to wipe it? No, because you said you only ate ass only "once" so that couldn't be it. I'm sorry, I'm having a difficult time visualizing what happened.