as someone with IBS, cold/frozen liquids are the way to go... pun fully intended. it might be a bit difficult to keep things cool, but frozen sports drinks and the like are good for keeping you going. it's really unhealthy, and i absolutely can't recommend it, but it should work. you get a lot of your water intake from food, too, so if it's not getting any of that, the water you ingest from liquids/frozen liquids is gonna get sucked up by your large intestine and, in theory, you'll need the toilet less. good luck with, uh. your thing.