I drink water (not tons of it, but more than sips) up until about 2 hours before drinking the oil, and I've never had a problem. In fact, I'm less nauseous, particularly in the morning, if I stay hydraded as much as possible. I also sip some juice, since my blood Sugar
tends to get low when I skip meals. I think the general idea is just to make sure you stomach is empty when you drink the oil at night, and that oil and water don't mix, and wouldn't mix well in your stomach. It sounds like a lot of people have developed their own tricks and modifications that work for them when flushing.