Emma and her family was driving down to Texas to see her Aunt. It was a long 8 hour drive. They drove a little ways when bowel gas hit her. Emma let out a stinky, loud tuba fart, that lasted a few seconds. Her siblings groaned at her and opened their windows. Emma frantically said to her father "When's the next pit stop?!" He checked the GPS. "We'll be there in 15 minutes." Emma groaned and held her stomach. When they finally reached the petrol station, Kelly, her elder sister, dashed into the lone toilet stall and Emma pounded on the door. "Kelly, please! I-I have to poop!" She replied "I have to poop, too! Just wait a bit!" Emma groaned and leaned against the wall. She heard Kelly farting loudly in the stall and a poop splashing into the toilet, making the pain even worse. A log of poop began to force itself out of her and she clenched even harder, letting out some high pitched farts in the process. Moaning, wet farts escaped her, each one making her turd poke out more. Giving up because of the intense pain, she let the poop go, at last silently sliding out with a wet fart. As she completely gave in, more turds began to slide out, the smell now very noticeable. With one last surrendering fart, a final massive log crawled out of her arse. It was official. Emma had just taken a massive shit in her pants. Checking behind her, she cringed as she saw the big stain and big bulge. The toilet flushing finally, Kelly stepped out. Emma tried in vain to rush past her and she saw the stain on her pants. "Emma, did you... poop your pants?" Emma turned around and nodded, tears falling down her cheeks. She closed the stall door and pulled down her soiled pants, shocked at how heavy they were. She saw her white panties stained beyond repair and cried with shame.