From what I have observed it's more of a teenage girl thing. I asked an ex girlfriend of mine when I was a teenager this same question. She told me it was to talk about their dates/boyfriends.

I always thought it was so they couldf chatter ?

Farting: Seven Surprising And Spectacular Health Benefits

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[huffingtonpost.com]

I have a shy bladder so it hasn’t been my thing. Although is I’m somewhere new or with a lot of people (concert etc) then I’m good with going in a group for safety.

A young friend of mines was bashed and robbed by a gang of girls in the ladies at a nightclub years ago, maybe going alone is not a good idea.

I always go to the bathroom myself right then, and the girls marvel that I never have to go.

Pretty sure this is a stereotype. I never go anywhere with other women. The women I know usually go it alone too.

I'm guessing that your upfront and tell people how you feel and go to the bathroom to use the facilities within. the woman who goes together aren't secure enough to do that and go to talk about people.

OMG girl. Women that go to the bathroom together are not doing so to pee together. They go so they can talk in confidence about what's going on at the club, restaurant, guys, bands, whatever!! That's what they do! I did it when I was young and I'm not one bit ashamed of it. Haha~

From the man's point of view: when a guy using a stall is talking on his phone...while pooping.

I don't get that either..and don't talk to me when I'm sitting on the pot..please.

To talk about me.

Not all women do that. Although, sometimes it is beneficial, in case there's no lock on the stall door, or if you need tp.

I can think of some reasons. One is they know by accompanying a friend, you prevent her from suspecting that you're talking about her when she isn't there; especially with the males.

Or, two, that anything males have to say to each other isn't worth sticking around for. The level of conversation probably improves in 'the other room'.

Maybe another is that it provides an opportunity for women to strut, as they seem unable to do it while sitting down...

I've always thought it was to dance in a ring of Christian blood to summon the Dark Lord and live deliciously out of sight from judging eyes.

Me neither!

My girlfriends and I still do that at times. When we are talking we are busy talking. If they are at my house, I never close the door, we talk non-stop.
If their kids are over at my house, I close the door.
Is just as girls. We don't care.

I've never experienced this either. I give the WTF are you doing look when I see it on TV or movies. Honestly thought it was something Hollywood made up because I've yet to witness it out in the real world.

I've always thought that was where women had their super-secret meetings to plot the subjugation of men.

Probably was for safety in the old days, but I am 78 and a feminist, and wondering what kind of women you are seeing that need this.