I was just in a hurry one morning and chugged the warm water very quickly and very quickly had a bowl movement. So I started doing that every day and it usually helps. Then I read--I think it was on this site--that drinking very warm water very quickly activates something in the brain kind of saying "this is important, so distribute the water correctly (including putting it in the intestinal tract) this time for a change." (You'd think it'd be the opposite, that sipping water slowly throughout the day would be calming and make things work better, but for some reason it doesn't.)