Accoucher de...what?

Just a quick anecdote from class yesterday...
Yesterday, we were having a conversation class, and one of the phrases we were working with was, "Elle vient d'accoucher d'un bebe" which means, "She just had a baby." Well, the ladies kept giggling and giggling, and I couldn't really think of anything that would be that funny about childbirth.
Finally, I asked them, "What are you laughing about?"
They shook their heads, mumbled, "Nothing."
We continued, talking about birth and babies and such, and they continued laughing.
I stopped again and said, "Really, what's so funny?"
Finally, one of my ladies said, "Accoucher," (to give birth) and they all started laughing again.
So, I said, "Is there something funny about the word 'accoucher'" and even as I said it, they all dissolved into giggles again.
One of my more advanced students who was laughing so hard she was in tears and had the coal from around her eyes running in streaks down her face said, "In Berber, 'accoucher' means..." and then, she started laughing again.
"It means something funny?"
She nodded.
"Like...what?"
She shook her head, and all the ladies started looking around at each other, shrugging.
So, the more advanced student whispered something which I didn't catch. I asked her to repeat it, and again, she said something completely unrecognizable. Asked a third time, she finally started making raspberry noises with her mouth. "Gas," she said. "It means when a person has gas."
And they all started laughing again.
We eventually just had to change the subject and abandon all hopes of discussing childbirth, because they all were laughing like third graders at the word "Accoucher."
While the lesson plan took quite a turn, I'm still glad that they seemed to enjoy themselves...