Sarah's small patch of exposed skin got James quite stirred up, but he immediately pulled himself together and carefully examined the entanglement of hair and zipper.
Perhaps Sarah had already tried to free it herself for a while, because now the hair and zipper were very tightly wound. James had to gently tease out Sarah's hair bit by bit, but the last part couldn't be done that way.
With his left hand, James grasped Sarah's hair—along with some fabric—and with his right, he took hold of the zipper pull. He tugged it up twice, then down once, and Sarah's hair was finally completely released.
However, such a yank brought the zipper down to Sarah's waist in a flash, and the dress fell open, revealing most of Sarah's back, along with the straps of her transparent bra clear in view.