From urban dictionary
When too much air builds up during insertion from the penis. When the penis is removed it results in the excretion of air buildup and is released without female control. “Farting”
As Jake was removing his massive dick from her wet pussy, she queefed.
www.urbandictionary.com
From women health Magazine
When Does Queefing Happen?
It often occurs during sex, when apenis going in and out of a vagina can displace the air inside of it. “It can happen during any position and is usually fairly quick,” says Minkin. Of course, that’s also just about the last time you would want to rip one. A queef can also slip out during exercise, like when you’re getting into downward dog or knocking out the last set of crunches.
http://www.womenshealthmag.com/health/queefing
So Guys, don’t go around town, chest thumbing how u ferked her so hard, that all she did the whole time was Farting.
She was queefing.