The song is about an obese Tasmanian woman, Rosie, with whom the singer (Bon Scott) had a one night stand at the Freeway Gardens Motel in North Melbourne. In addition to pointing out the woman's size, the singer finds her to be one of the most talented lovers he's ever experienced.
The tales and legends around the song have become almost as wildly inflated as the cartoonish stage prop that has appeared behind the band in concerts,” Fink wrote. “But Rosie is now firmly etched into rock mythology.” He added: “On the 1976 tour, Bon supposedly was yanked into a random doorway by a 42-39-56-proportioned woman while walking the streets after a gig. ... Rosie, as she would become known, was with another girl at the time, and Bon went off with both of them to their shared room.”
He cited an interview in which Scott claimed, “‘She’d have broken my arm if I’d refused,” and elsewhere said, “She was so big she’d sort of close the door and put it on you... she was too big to say no to. So I just sorta had to succumb... I had to do it. Oh my God, I wish I hadn’t.”
Fink’s investigations extended across Australia and resulted in a number of suggested identities, with even the mayor of one town claiming he knew the real Rosie. “But my experience has been that those individuals who boast they know Rosie today never seem to come up with any details beyond what is already available on the internet or in books; they add nothing new to the story,” he said.