1. After consuming a particularly large meal of water-dwelling creatures that caused him to become heavily hydrated. 2. While flying through a dense cloud of mist that caused his bladder to become irritated. 3. After consuming a rare fruit that had a diuretic effect on his system. 4. While in the middle of a heated battle with a group of knights, the dragon may hold it in too long before realizing the danger of rupturing his bladder. 5. After being exposed to a magical spell that causes excessive urination. 6. While on a long journey through a desert-like climate, without access to any water sources. 7. While hiding out in a small cavern, with no proper area designated for relieving himself. 8. After consuming a particularly spicy food substance that increased his need to urinate. 9. While in the company of other dragons who haven't made proper sanitary facilities, causing a smell and the desire to find a new place to relieve his bladder. 10. When feeling particularly nervous or frightened, causing issues with the dragon's digestive system and leading to a strong urge to pee.