Well of course you use those to dry your underwear!!!!
Somebody on a flight from Turkey to Moscow posted a video of a woman drying some underwear by holding them up to the overhead air vent. Not sure if they were her's or not. I am hoping she washed them in the airplane bathroom beforehand, and the scent of dring urine was not wafted throughout the plane. Apparently, she held them up for "at least 20 minutes." Good times.