Answer:
Claire: "Bill, can you explain these panties to me?"
Bill: "Yes Claire. It appears to be a thong, black lace, size medium. They are for wearing underneath pants and sometimes for more risque behavior. The small part goes in the back."
Claire: "I understand how they work Bill, you don't have to be facetious. What I want to know is why they're here, and more importantly to whom they belong."
Bill: "You mean they're not yours?"
Claire: "Maybe now you'll give me a serious answer?"