There is and has been for a long time quite a business in soiled panties. In the 80s I spent some time with a lady who ran her own small mail order business in them. She advertised trough want ads in the back of the more risque local zines. She would wear them. Write a note about what she had done while wearing them. Stick them in a plastic bag and send them off. She even had regular subscribers who wanted regular packages. She also would have them send what they wanted her to wear to her PO Box. From time to time she included Polaroid pictures. IIRC she was able to charge a premium for additional soiling.
My eyes and mind were opened. Since then, I have never been surprised.
-mS