[Noah930]

The colonoscope has only a couple maneuvers. There are two knobbed wheels that control cables to either deflect the tip of the scope up-down, or left-right. Each wheel controls one axis. Combine the two, and you can angle the scope in any direction (think drawing a circle or curved line on an Etch-a-Sketch). You can even turn the tip of the scope 180 on itself to "look backwards" on itself. To drive the scope, you typically use one hand to advance the scope into the colon (or pull it back out). Simultaneously you're deflecting the tip of the scope to steer it through the colon.

Then there's an irrigation feature. You can squirt a little saline. There's a suction.

And there's an insufflation. That's what causes the post-procedure gas. The colon is normally going to be pretty collapsed. In order to see anything, you have to fill the colon up with some gas a little bit like a balloon. There's air constantly pumped through the scope. There's a little relief hole at the control end where air escapes, unless the operator puts their thumb over the hole to obstruct it and allow the air to pass down the scope and exit out the tip (presumably inside the colon). Thumb over the hole, and the colon fills up with air. Release the thumb from over that hole, and no more filling of the colon. You want to blow up the colon to allow visualization. But at the same time, if you fill up the colon with too much air, that causes the patient pain, as intestines have stretch receptors in their walls. As you come out, you always manage to leave a little air in the colon, even if you try to suction, which is why patients are a bit farty afterwards.