Definition of "thonged"

It helps that the dozens of veiled and uneducated female laborers who assemble the handmade items — gag balls, lime-green corsets, thonged spanking skirts — have no idea what the items are used for.

2009 April 28, Adam B. Ellick, “Lacy Threads and Leather Straps Bind a Business”, in New York Times‎