On numerous occasions I’ve been in a restroom and have heard somebody loudly pass gas while they were in the process of urinating. While I cannot prove any statistical relationship between the two occurances, I’ve heard far too much farting taking place during the brief urinary interval to believe that they aren’t interrelated.
What is the physiologic mechanism by which urinating causes a person to pass gas?
Thanks.
Said the dowager duchess at tea,
“Young man, do you fart when you pee?”
I replied, "Not a bit!
“Do you belch when you shit?”
Which I’d say left the honours with me!
Well you’re at it, my wife wants you to tell her why men fart when they enter the bedroom.
I’d say it’s two parts.
You’re relaxing muscles in the lower abdomen, that are related to waste. The fart “leaks” out.
The bathroom is the one place that no matter how stinky the fart is, you are actually allowed to let it go there. You’re standing around at the urinal anyway, what else do you have to do. It’s just a good time to get nice beefy fart in. 
I think this only works if there is only one egress from the bedroom. That way she is trapped and if she tries to flee we can clothes-line her when she tries to run past us in a panic. Still not as good as holding her head under the covers, but they start expecting that after a few times and the shock value wears off.
There are sphinctor muscles that close both the urinary and anal openings. The nerves controling these are seperate, I believe, but most people have learned (potty training) to control them somewhat together. Notice that most people open both to poop, and can’t poop without also peeing?
So when men are opening the urinary sphinctor muscle to pee, they tend to at least loosen the anal one, thus allowing a fart. And, as people mentioned, our culture makes the bathrom an acceptable place for farting, so this behavior is reinforced.
I met that same duchess at tea.
It was just as I feared it would be:
Her noises abdominal
Were truly phenomenal,
And everyone thought it was me.
Where I come from this is called a “Covered Wagon”
Heh. 
“Dutch Oven” around here…
It’s a guy thing-to let go a magnificent trouser growl in the acoustical environment of a public men’s room, then zip up and walk out with a smile on your face because you’ve done as suggested by Benjamin Franklin: Fart Proudly! 
Revenge needs just a small chance,
so I humbly asked her to dance
I pulled down her drawers
clean down to the floors
to show she had brown in her pants
OK, that sucked, but it was still fun.
I heard of a brand new marriage that ended abruptly with a ‘Covered Wagon’…picture a wedding night, and the happy new groom does this to the startled, revulsed, and disgusted new bride. And laughs at her, because “it’s a guy thing and it’s funny.”
End of marriage.
I wish I could remember where I heard about it. Probably the same place I heard about the marriage that was anulled directly after the new groom asked his bride to lie in a bathtub full of cold water for a while, then lie perfectly still on the bed.
Personally, I’d like to know what it is with ‘morning farts’. Kids get up, sit on the toilet, brrrrrrrrap. My own digestive system seems to kick into gear when I wake up, too. Very strange. I theorize that while sleeping, the rhythmic movements of the digestive system still, and gas builds up as it always does. But because there is no movement, the gas just sits there until waking creates peristaltic movement. Would I be correct on this?
“A leak without a fart is like a wedding without a band.”
Famous quote around the office from our financial guy.
-rainy
Why has no one mentioned women who fart while peeing. Is it a man-only event?
I like the Google ad for Gulf Hurricane Relief!
Partially. It has more to do with you being still and hortizontal for a long period of time. Moving around helps the gas work its way through one’s system. When you awaken, the act of moving around helps free the gas that has built up naturally over night. That is also the reason that babies need to be burped after a feeding. They don’t have enough mobility to help the gas along on their own.
Women don’t fart. They can’t. They won’t keep their mouth shut long enough to build up any back pressure.
I believe the latest term is a “Hugo Boss.” From their advertising campaign “your fragrance, your rules.”
Umm…no. Or else I’m some sort of weird anomaly. It’s not every time, but quite often.
Ok here is the biological reason… The urinary and digestive system is control by the parasympathetic nervous system. The there two sphincter muscles (termed intern and external) in the urinary tract and at the end of the digestive tract. One is involuntary (internal sphincter) which is under control of the parasympathetic nervous system and one under voluntary (external sphincter) muscle control. The bladder, when full, signals the PSN to to relax the internal sphincter muscle. This CAN also send a signal to the internal sphincter muscle in the rectum which could permit gas to pass freely. The external sphincter muscles, under voluntary control, are consciously relaxed, when they do you can more easily pass gas. If you try to “clench” the anus to prevent farting it can cause most of the lower abdominal muscles to tighten up making it more difficult, and sometimes more painful to pee. So, most men just choose to relax those muscles and pee (and fart) without impediment.
Do women as often, then?