What does air wash mean?

air wash meaning in Urban Dictionary

The act of airing out your day-old clothes when you don't possess a change of clothing useful. Frequently happens after getting drunk at happy time and crashing at another person's pad on a work evening. Can also occur due to bad laundry supply management abilities (i.e. running-out of clean clothing since you're also lazy to complete a wash). Specifically relates to underwear. Perhaps not almost as effectual as water, but yet provides a hint of hygiene, albeit limited to a couple of seconds.