Slavery: A series of erotic games (book 01)
It was backless and the only zipper on it was over my butt so I could wiggle into it and have it be tight across my ass.
"Excuse me, Gwen, but I seem to be having difficulty with this zipper, could you please give me a hand."
Of course I was having problems with the zipper. It was at least one size too small. She came into the dressing room with me and tried zipping it up, noticing in the process I had no underwear. The zipper didn't go low enough to reveal my plug, but wasn't far removed from it.
"I think you picked one out too small for you. Can I get a couple larger sizes for you to try on?"