I do both. The first wipe is a scout, I do it sitting down. Usually just to check how things are going, but lately I'm getting the bunny tail poop where I have to do at least 3 sitting wipes to get it off. Then I stand up, present my butt like a submissive slut and continue wiping until clean, alternating between directions. Some time ago I used to get the so called clean poops, where they come out in one, solid ingot, and leave the anus area completely clean. Those were glorious days, but I really don't know what causes the difference in shit structure.
Hope it helps.