got the rear of her skirt caught in the zipper.
shirt was poking out through the fly and got caught in the zipper.

Oh, yes--I remembered I'd read some time ago where an author was at that movie theater. 'Never Give a Sucker an
Even Break' was showing. The incident between the portly man and the lady gave him the germ of an idea, but he couldn't flesh it out until he had his own experience with the second phenomenon described above. And thus was the inauspicious beginnings of P.D.Q. Salinger's "The Catcher in the Fly".