For a much cleaner pee-only version, see “>>[Derpibooru]2159393”:https://derpibooru.org/images/2159393
 
Apple Bloom hadn’t been feeling the best the entire afternoon, but it was only a couple of minutes until the end of the school day. Of course, that’s when her stomach started to protest in force. At first it came in short waves of discomfort in her belly, but quickly grew to an all encompassing sickness in her bowels. The filly pressed her tail down flat against her rear as hard as she could, and for a moment she thought she could hold it, but soon her stomach gurgled and the head of a slimy horse apple pushed its way into her panties. Her tail hiked up and after that it all happened so fast. Log after log of softer and softer horse apples poured out of her and her panties bulged and leaked as she was uncontrollably sick in her undies. By the end what came out of her was almost completely liquid. The smell was beyond terrible…

imported from https://derpibooru.org/images/2160399