What if the human body doesn’t fart, poot, bubble, puff, or eliminate air? Make a Raspberry. Lay an egg. Step on a frog or loose floorboard. Sit close to the Labrador dog or Grandma.(
)
Rev the motor. Blow stank. Lose your good manners.
Clear the bench. Or elevator.
Make fog. Rip one. Cut the cheese.
Rouse the duck. Backfire.
(I live with preteen boys, I could go on forever)
Any whoo, is it dangerous not to let the air out?
You could stick a pin in them and watch them fly around the room.
Years ago my crazy sister was having all kinds of intestinal problems and cramping. Long story short, doctor told her to fart more.
Ain’t modern medicine somethin’?
Just make sure you let it all out before laser intestinal surgery, lest you cause an explosion.
Unfortunately for you, this is a species that considers farting to be a competitive sport.
You might have to get your appendix removed:
This is true. One of the boys can fart on command. We’ve just recently convinced him he doesn’t get brownie points for this bit of skill.
If he farts at the wrong time, he will get brownie points.
You don’t get any money. No, wait, that’s GO You collect $200 for passing GO, not for passing gas. 
If he tries too hard, he may get brownie pants 
After a certain age, Never Trust A Fart!
What if I don’t pass that gas? That is a question which may never be answered.
Age 9 is too old?
I think there’s inconsistency, here.
Old yeah, fart=squeeze the catfish.
No matter how tightly you try to hold it, the sphincter is still the weak spot of the bowels. It will leak out eventually.
Most of the time, yes.
To answer the title question, some of that gas is reabsorbed in the colon when one refuses to pass it. Most of the rest will inevitably be expelled during a bowel movement, which over time will become more urgent.
It is possible that pent up gas could rupture a colonic wall defect, such as a eroded diverticulum or ulceration. But gladly that’s not real common. In those cases it’s the erosions that tend to cause punctures or blockages that then cause a blowout under pressure.
Ahh, the ol’ childhood adage “why fart and waste it, when you can burp and taste it?”
“A fart is the lonesome cry of an imprisoned turd.” So true. 
Another name for farts my grandkids use: Butt burps. I laughed at that one.
Thx for the info Doc. That’s truly alarming.
Heh. I was in a community theatre production of 12 Angry Men. At some point before the run, the director—a woman—was interviewed about the production by the local paper.
When asked what it was like to be the only woman in the midst of all those men, she replied, “Well, when not rehearsing, their conversation tends to be about sports, women, golf scores, and fart jokes.”
@Dung_Beetle say that in Attenboroughs voice. Please
Would such a command be considered an illegal order?