system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are we not literally shitting the bed often?

Since being married I've learned that we all fart in our sleep. My wife does it, but she claims I do it a lot.

At the same time, I'm sure we've all trusted a fart we shouldn't have in our lives. So how is it our unconscious self has better control over our bodies than our conscious self?

At first I thought the answer was simply pressure. Enough pressure builds up and just forces it's way out, while our waking self usually tries to force it. But I'm sure there's times #2 has plenty of pressure to force it's way out also.
gpt
Essentially you kind of do.  When you fart, tiny bits will fly out.  However, it's easier for gas to accelerate quickly out of the opening in the sphincter than large solids that are easily seen.   If you blow on a paper wad or something, you'll see how much air you have to blow to propel a solid forward.  It really doesn't take much gas leaving the bowel to relieve the pressure.

If you have enough pure solid in your Colon to force it's way out without gas, you're likely going to wake up, unless you are drunk/drugged, which is why those folks do occasionally shit themself.